B GIAO DUC VA AO TAOAI HOC VO TRNG TOANB MN C CHT HOC

GIAO TRINH

C CHT HOC(DUNG CHO SINH VIN DC)

Bin soanPGS.TS. HOANG TRONG SI

CN TH-2015

I CNG V C CHT HCNHNG VN C BN CA C CHT HC

I. I CNG V C CHT HC1. C CHT HC, NHIM V V CC LNH VC CA C CHT1.1. inh nghia: c cht hc l mt ngnh khoa hc nghin cu v cc cht c, cc tc hi ca chng trn c th con ngi v ng vt, cch phng, chng v ngn cn cc tc hi .1.2. Nhim v c bn ca c cht hc Nhim v u tin ca c cht hc l nghin cu pht hin v xc nh cc cht c, cc tnh cht c hi ca cc cht ho hc c kh nng gy nhng bin i sinh l trong c th ngi v ng vt. nghin cu cc iu kin cht c c th gy ng c. Xc nh vng tc ng ca cc cht c: cn c vo liu ti thiu gy ra s ri lon chc nng ca c th, ngi ta xc nh vng tc ng ca cc cht c. Nghin cu cc du hiu lm sng v bnh hc ca nhng trng hp ng c m cc cht c xm nhp theo cc ng khc nhau vo c th. Cn xc nh c bnh cnh v mc tc ng...Vic xc nh c cht c tc ng ti c quan no c ngha quan trng c v l thuyt ln thc tin. cn c vo c th chn on c nguyn nhn gy ng c, tin lng c qu trnh din bin ca ng c, a ra c cc phng php x tr v iu tr, gim thiu cc tc hi do cc cht c gy ra. c cht hc cn x l cc s liu thc nghim trn c s ca php ngoi suy tnh liu c ca cc cht c i vi ngi v ng vt. Trn thc t, khi nghin cu xy dng liu c ca mt loi thuc cn phi th c tnh ca thuc trn cc ng vt th nghim, t cc kt qu thu c, nhim v ca c cht hc l phi tnh c liu c ca thuc cho ngi. c cht hc phi gii quyt cc vn c lin quan ti nhiu lnh vc, c bit cc ngnh khoa hc t nhin: ho v v, ho hu c, sinh l, ho sinh, di truyn, min dch hc...Da vo c th nh gi mc tc ng ca cc cht c ln cc c quan, t chc, t bo hoc phn t ca c th con ngi v ng vt.1.3. Cc lnh vc ca c cht hcTheo quan nim hin nay, c cht hc bao gm mt s lnh vc: c cht hc i cng: nghin cu pht hin cc qui lut tc ng ca cc cht c ln cc c quan ca ngi v ng vt. c cht hc d phng: nghin cu xc nh mc nguy him, a ra cc bin php x tr, ngn chn v d phng cc tc hi ca cht c i vi sc kho con ngi, ng vt v mi trng. bao gm cc lnh vc: cng ng, thc phm, cng nghip, nng nghip v dch v... c cht hc lm sng: nghin cu cc bnh do cht c gy nn. Bao gm cc ng c cp tnh, ng c mn tnh, nghin ma tu, ng c thuc... c cht hc chuyn ngnh: nghin cu cc ng c i vi ngi v ng vt trong nhng iu kin v hon cnh c bit. Bao gm cc lnh vc: c cht hc qun s, c cht hc hng khng v v tr, c cht hc php y... Kim nghim c cht phc v cng tc iu tr v t php: kim nghim c cht gip cho vic chn on, pht hin nguyn nhn gy ng c iu tr kp thi, ng thi kim nghim c cht c nhim v phc v cc c quan t php khi cn thit.2. KHI NIM CHUNG V CHT C, C TNH V NG C2.1. Cht c. Trong c cht hc ngi ta quan nim cht c l nhng cht khi a vo c th d vi mt lng nh, trong nhng iu kin nht nh s gy ng c cho ngi v ng vt v c th dn n t vong.Trong thc t cho thy khng phi lc no cng c mt ranh gii r nt phn bit cht c v cht khng c. Nhiu nguyn t v c tn ti trong c th vi mt lng nht nh c vai tr sinh l; nu vt qua gii hn s gy ri lon, Schwartz dng thut ng "ngng nng " (concentration window) vch ranh gii phn cch .2.2. Ng c. Ng c l trng thi bnh l do s tc ng ca cht c lm ri lon cc hot ng sinh l ca c th ngi v ng vt.Trong thc t khng tn ti mt cht c tuyt i. Mt cht ch c th thnh cht c trong nhng iu kin nht nh. Cc iu kin rt khc nhau v a dng.Mt cht tr nn c, trc tin ph thuc vo liu lng ca n trong c th. V d: trong c th ngi cc hocmn lun c tit ra iu ho chc nng cc c quan, nu v mt l do no hocmn c tit ra nhiu qu th s gy ri lon hot ng ca c th. Cc nguyn t I-, F-, ZnII, CuII, MnII, CoII...l cc nguyn t vi lng trong c th, chng gi vai tr nht nh trong hot ng sng, nhng nu cc cht ny vt qu ngng sinh l s gy ng c.2.3. c tnh (toxicity): l thut ng dng m t nhng tc ng xu ca cht c ln c th sinh vt. Tu thuc vo mc ca c tnh, cht c c th gy cht, hoc gy tc hi ln tng c quan ca c th. c tnh l mt khai nim nh lng. Hu nh bt k cht c no cng u gy tc hi vi mt liu (dose) no ti cng mt thi im. Bin gy hiu ng c ca cht c dao ng rt ln: t liu gy c man tnh n liu gy cht tc khc.* c tnh cp: biu th tc ng xu hay t vong ca sinh vt ngay sau khi tip xc vi cht c. c tnh cp xy ra do tip xc vi mt hoc nhiu cht c trong phm vi mt thi gian ngn ( 24 gi)* nh gi c tnh cp: xc nh kh nng gy hiu ng c ca cht c. y l mt nh gi inh lng phn nh c tnh ca tng loi ho cht c. nh gi c tnh cp thng lin quan n tnh t vong thng qua vic c lng LD50 hay LC50:+ LD50 (median lethal dose 50): l liu c lng, khi cht c c a trc tip vo ng vt th nghim m kt qu l gy cht 50% qun th tip xc vi cht c di nhng iu kin xc nh ca th nghim. Gi tr LD50 c xem nh l tiu chun so snh c tnh cp gia cc cht c vi nhau.+ LC50 (median lethal concentration 50): l nng c lng trong mi trng m ng vt tip xc v s git cht 50% qun th tip xc vi cht c di nhng iu kin xc nh ca th nghim. Bnh thng ngi ta s dng LC50 thay th LD50 trong nghin cu c hc mi trng nc (aquatic toxicology) v c hc mi trng khng kh (inhalation toxicology).+ ED50 v EC50. Nu nh im cui ca th nghim khng gy cht ng vt th nghim m cc nng th nghim dn n cc tc ng (bt ng, bin i hnh vi...) khc nhau i vi 50% ng vt th nghim th gi l liu tc ng 50%: ED50 (median effective dose) hay nng tc ng 50%: EC50 (median effective concentration).* c tnh mn: m t nhng hiu ng xu xut hin sau mt thi gian di tip xc vi nhng liu lng nh cht c. Phn ln biu hin nghim trng nht ca c tnh mn l gy ung th, tuy nhin nhng biu hin khc ca c tnh mn cng c bit, v d nh tc ng n s sinh sn, hnh vi...3. TC DNG CA CHT CCc cht c khi xm nhpvo c th bng cc con ng khc nhau v c phn b ti cc t chc , c quan. N tp trung cc c quan, t chc no nhiu hay t, ph thuc vo tnh cht l ha ca cht c v iu kin xm nhp vo c th. Cc cht c tc ng ln cc t bo v lm ri lon hot ng sinh l ca chng. Nhn chung cc cht c tc ng ti mt s c quan:3.1. Tc dng vo mu: Mu bao gm huyt tng, hng cu, tiu cu, bch cu. cc thnh phn ny u c th b thay i bi tc ng ca cht c.* Huyt tng: cc thuc m nh chloroforrm, te, lm gim pH, gim d tr kim v tng kali ca huyt tng. Nc rn s nh hng ti qu trnh ng mu: nc rn ca mt s loi s lm tan huyt, cn mt s loi li lm tng kh nng ng mu, nh mt s loi rn lc s lm tng kh nng ng mu.* Hng cu: s lng hng cu trong 1 cm2 s tng khi nhim c kh clo, photgen, chloropicrin gy ph phi cp v lm mu c li do hut tng thot ra nhiu. Hng cu b ph hy khi: ng c ch, nhim tia X, nhim c benzen, cc dn xut ca cc amin thm...Kh cacbon oxit lin kt vi hemoglobin to phc cht cacbonxyhemoglobin lmg mt kh nng vn chuyn oxy ca hng cu, c th gy nn cht ngt. Cc dn xut ca nitro thm, anilin nitrat... c th oxi ha Fe2+ trong nhn hemoglobin thnh Fe3+, chuyn n thnh dng methemoglobin, lm mu khng c kh nng vn chuyn oxi.* Bch cu: s lng bch cu b thay i do tc ng ca cc cht c. Khi ng c cc kim loi nng s lng bch cu s tng, ng c benzen s lng bch cu gim, gy thiu mu.* Tiu cu: khi ng c benzen s lng tiu cu s h t 200.000 - 400.000 xung cn vi chc nghn.Mc khc, di tc dng ca cht c, mt s thnh phn mi xut hin trong mu: khi ng c ch trong mu xut hin cht copropocphirrin, ng c axit mnh xut hin cht hematopocphirin. Da vo cc cht ny, ngi ta c th chn on ng c.3.2. Tc dng ln b my tiu ha: Cc cht c khi xm nhp vo c th qua ng tiu ha thng gy nn ma nh ng c thy ngn, thuc phin, photpho hu c... l phn ng u tin ca c th i vi cht c, cc cht c tc dng ln h thn kinh lm c honh co bp mnh dn ti nn ma. Cht c lm tng tit nc bt nh khi ng c cc thuc tr su ln hu c, nm v mt s kim loi nh ch, thy ngn, bitmut; hoc ngc li lm kh ming nh ng c atropin hoc cc ph phm beladon. Cc cht gy kch ng ng tiu ha nh cc axit hoc kim mnh; gy chy mu ng tiu ha nh cc thuc chng ng mu, cc dn xut salixilat; c trng hp gy kh tiu hoc tiu chy.3.3. Tc dng trn gan: Gan l mt b phn nm ng t ng tiu ha. T tnh mch ca, bn cnh cc cht do chuyn ha thc n cung cp, gan nhn tt c cc cht c. Gan l c quan chuyn ha cht c ca c th. Nh h thng enzym ca gan cc cht c c chuyn ha t cc cht ban u thnh cc cht khng c hoc c tnh c thp hn, thun li hn cho qu trnh o thi khi c th.Mt khc, ng mch trn gan a mu vo gan v ti u khp. Do cc cht cha trong mu qua h thng i tun hon u c tc dng ti gan. Khi nghin ru lm x gan, teo gan; ng c mt s loi nm gy vim gan, ung th gan, ng c asen gy tn thng cc t chc gan, thoi ha m; vng da khi ng c AsH3.3.4. Tc dng ln h tim mch. Nhn chung cc cht c khi xm nhp vo c th c nh hng rt ln n h tim mch: c cht lm tng nhp tim nh cafein, adrenalin, mphetnmin... cc cht lm gim nhp tim: digitalin, cc thuc tr su ln hu c. Khi ng c cc cht t gan v nha m cc lm mch khng u. Ng c quinidin, imipramin c th gy ngng tim ...Mt s cht nh hng n mch mu: acethylchlolin gy gin mch, nhng khi ng c cc ancaloid ca nm ca la mch s lm co mch.3.5. Tc dng trn thn. Cc cht c ch yu c thi qua thn bng nc tiu ra ngoi. Do vy thn l c quan quan trng trong qu trnh thi c, cc chc nng ca thn u b tc dng ca cc cht c khi b ng c. Thy ngn, ch, cadimi lm tng ur v anbumin niu. Axit oxalic, thuc chng ng mu, cantharid gy i ra mu. cc dung mi hu c c chlor nh chloroform, dichlorometan gy vim thn. Nhiu cht gy v niu nh thy ngn, sunfamid, mt c trm...Nc tiu l mt loi mu th quan trng trong kim nghim c cht.3.6. Tc dng ln h thn kinh. Hu ht cc cht c u t nhiu tc dng ln h thn kinh, gy ri lon chc nng vn ng hoc cm gic.Cc thuc m nh: te, chloroform tc dng ln no v ty sng lm mt phn x, c th gy ngng th do chng tc dng ti hnh no. Ng c ru, thuc ng, thuc phin c th dn ti hn m do c ch thn kinh trung ng. Cc cht kch thch thn kinh nhm amphetamin, long no, cc thuc tr su nhm chlor hu c kch thch thn kinh gy trng thi vt v, thao cung. Ng c stricnin, m tin gy trng thi co cng do kch thch ty sng qu mc.Cc cht tc dng ln h thn kinh giao cm gy gin ng t nh adrenalin, ephedrin. Ngc li mt s cht lm co ng t nh axetylchlolin, prostigmin do c ch thn kinh - th dch, tc dng vo cc cht trung gian nhy cm dn truyn thn kinh hoc trc tip tc dng ln cc th th.3.7. Tc dng ln b my h hp. Khi cc cht c xm nhp vo c th quan ng h hp c th gy cc tc dng ti ch hoc ton thn. Cc tc dng ti ch ln ng h hp ca cht c biu hin: gy hc hi, ho , tng tit nc mi, nc bt do cc cht c kch ng ng h hp nh CS2, cc cht kh gy ngt.Cc cht c gy ngt c ch h hp t bo gy tm ti nh kh CO, ng c kh CN, ng c sn... c ch h hp gy ngt th nh thuc phin, thuc ng... Mt s cht c th gy ph phi cp: H2S cc thuc tr su nhm ln hu c.4. CC YU T QUYT NH TC HI CA CHT CC nhiu yu t quyt nh tc hi ca cht c i vi c th, trong nhng yu t quan trng nht l: cu trc ho hc, tnh ho tan, tnh bay hi, nng v thi gian tc dng ca cht c...4.1. Cu trc ho hc ca cht cTheo Lazarev, cu trc ha hc quyt nh tnh cht l ha v hot tnh ha hc ca c cht. Nhng tnh cht trn li quyt nh hot tnh sinh vt hc ca c cht.Visacscon a ra qui lut hot ng cc cht ha hc da vo cu trc ha hc:+ Cc hp cht cacbonhydro c tnh c tng t l thun vi s nguyn t cacbon c trong phn t, th d:Pental (5 C) c hn butan (4 C); Butylic (4 C) c hn etylic (2 C)+ Trong nhng hp cht c cng s nguyn t, nhng hp cht cha t nguyn t c hn cc hp cht cha nhiu nguyn t, th d:

Hot tinh hoa hcTinh cht l hoaCu truc hoa hcHot tinh sinh vt hc

Nitrit (NO2) c hn nitrat (NO3), oxyt cacbon (CO) c hn cacbonic (CO2)+ Khi nguyn t halogen thay th cho hydro nhiu bao nhiu trong cc hp cht hu c th c tnh tng ln by nhiu, th d: tetracloruacacbon (CCl4) c hn chloroform (CHCl3)+ Gc nit (-NO2) v gc amino (-NH2) thay th cho H trong cc hp cht cacbua vng bao nhiu th tnh c tng ln by nhiu, th d:Nitrobenzen (C6H5NO2) c hn Benzen (C6H6)4.2.Tnh ha tanCc cht d ha tan trong nc cng d gy c.V d : As2O3 tan gp 3 ln so vi As2S3 nn c tnh c hn. Cc cht d tan trong dch th v trong m li cng lm tng tnh c. nh gi mc c hi , ngi ta dng h s Owerton-Mayer, l t s gia mc ha tan trong m v mc ha tan trong nc. H s cng cao tnh c cng nhiu. V d: Benzen c h s O.M l 300 c hn tylic ch c h s O.M = 2.5, do benzen thm nhp v trong m ca t chc thn kinh nhanh hn.4.3. Tnh bay hi Cc hp cht d bay hi s to thnh trong khng kh ni lm vic mt nng cao lm tng t trng ca khng kh ln 25%; (dicloretan, carbon disunfua); trong tc ri xung ca hn hp hi s tng ln; v th chng s tch ly ch yu khp cng lm vic.4.4. Nng v thi gian tc dng ca cht cNng cht c trong khng kh cng cao thi gian gy nhim c cng nhanh. Thi gian tc dng cng nh hng n mc nhim c, mc tip xc cng lu th hp th cht c cng nhiu.Trong thc t sn xut, i khi ni lm vic cng mt lc c nhiu cht c, chng gy ra tc dng tng hp, thng gp trong cng nghip khai thc ch bin du m, cng nghip si visco...Tc dng tng hp ca cht c rt quan trng, cn c vo ngi ta quy nh nng ti a cho php. Nng ti a cho php l nng khng gy ra nhim c cp tnh v tip xc trong mt thi gian di cng khng gy ra nhim c mn tnh.Khi mi trng lao ng c hai cht cng tn ti v chng c tc dng tng hp th nng ti a khng vt qu 50% tng s nng ti a cho php ca 2 cht. V d: nng cho php ca benzen l 0,05mg/l l toluen l 0,1 th nng cho php ca 2 cht l 0,025 + 0,05 = 0,075mg/lTrng hp c 2 hoc nhiu cht c tc dng ngi ta quy nh nng tm thy trong khng kh ca cc cht ny so vi tng s nng ti a tng ng khng c vt qu 1,biu th theo cng thc.

Trong : C1, C2, Cn: nng cht c tm thy trong khng kh t1, t2, tn : l nng ti a cho php tng ng Tc hi ca cht c cn ph thuc vo cch s dng cht c, tnh trng sc kho v tui tc. Nhiu khi mt cht s tr nn c hn khi c mt ca cht khc (synergie): bacbiturat tng kh nng tc dng khi c mt ru; hoc tr nn t c hn (antagonism): hp cht photpho hu c gim c tnh khi c mt atropin.5. NGUYN NHN GY NG CTrong thc t, c nhiu nguyn nhn dn n ng c, sau y l mt s nguyn nhn ch yu5.1. Ngh nghip. Trong qu trnh lm vic thng xuyn tip xc vi cc cht c c th dn n ng c, trong trng hp ny, thng gi l bnh ngh nghip; v d nh cng nhn lm vic trong nh my acqui ch b nhim c ch, cng nhn trong nh my xi mng b bnh bi phi...5.2. nhim mi trng. Sng hng ngy trong mi trng (khng kh, nc, t...) b nhim.5.3. S dng thuc. Khi s dng thuc c th do nhiu l do gy ng c. C trng hp v qu mn cm nn b ng c ngay liu iu tr. Nhng thng thng ng c l do dng qu liu, dng nhm thuc hoc b d ng thuc.5.4. Thc n. Thc n i thi, c c t do vi khun tit ra gy ng c.5.5. C tnh t st hay b u c- Do b u c: k gian ch ng dng thuc u c bng nhiu th on- Do t t: nn nhn ch ng dng thuc t u c.6. S HP THU, PHN B, CHUYN HO V O THI CC CHT C6.1. S hp thu cht c. Cc cht c c th xm nhp vo c th bng nhiu ng khc nhau: ng tiu ho, ng h hp, ng da v nim mc.6.1.1. ng tiu ho. a s cc cht c c hp thu qua ng tiu ho theo cc c ch khc nhau. Cc cht c c th c hp thu ngay khi vo ming, hoc qua nim mc ming v sau qua nim mc d dy, c bit l hp thu qua nim mc rut bng c ch khuych tn qua mng, c ch thm thu hoc c ch vn chuyn tch cc qua mng. Cc cht c vo mu ri n cc c quan t chc.S hp thu ca cc cht c qua ng tiu ho ph thuc rt nhiu vo tnh cht l, ho hc ca chng. Cc cht d ho tan trong du m c th c hp thu tt qua ng tiu ho. Cc cht thuc thuc loi axit yu nh cc thuc ng nhm bacbiturat, cc dn xut salixylat, cc nitrat c hp thu tt d dy. Cc cht c tnh kim nh aminazin, cc alcaloid: mocphin, codein, resecpin, ephedrin...d dng hp thu qua rut. S hp thu cht c cn ph thuc vo trng thi v chc nng cc c quan: d dy do c pH thp nn ch thch hp cho vic hp thu cc cht c tnh axit yu, cn pH ca rut cao hn v c h thng enzym c th nh ho cc cht tan trong du, m nn thch hp cho vic hp thu cc cht c tnh kim v cc cht tan trong trong du m tt hn. Mt khc d dy cng rt kh hp thu cc phc hp c tnh bn vng ca cc cht c vi protid nh phc ca cc kim loi nhm kim th vi protein.6.1.2. ng da. Khi cc cht c ri vo da chng c th hp th qua nim mc da, qua l chn lng v ng thot ca tuyn m hi, tuyn nhn. Hp th qua da c mt ngha quan trng v chng thng xuyn xy ra trong thc t sn xut v i sng, c s tip xc vi cc ho cht c hi.Cc cht c c th tan trong du m d dng c hp thu qua nim mc da: cc thuc tr su ln hu c, benzen, tetrachlorocacbon, anilin...Mt s mui ca cc kim loi nng nh thu ngn, thallium cng c hp th qua da do cht nhn ca cc tuyn tit ra nh ho, gip chng c th thm qua nim mc da hoc theo cc l chn lng v cc tuyn vo c th.6.1.3. ng h hp. a s cc cht c bay hi v cc cht trng thi hi c th hp th qua ng h hp. Cc cht c s c hp th ngay t ng h hp trn, nhng s hp thu tt nht s xy ra ph nang ca phi, do din tch ca cc ph nang rt ln t 100-150 m2. Cc cht c c hp thu qua ng h hp ch yu theo c ch khuych tn n gin t ni c nng cao n ni c nng thp. Tc ca qu trnh hp thu ph thuc vo tnh cht l, ho hc ca cc cht c, vo nhp th ca bnh nhn v lu lng mu trao i qua phi. Hp thu qua ng h hp thng gp trong cc trng hp: ng c cc cht c qun s, cc kh c nh: CO, CO2, SO2, kh metan, cc thuc tr su, ru v ete...6.2. S phn b cc cht c. Sau khi cc cht c xm nhp vo c th, chng i vo mu, mt phn tn ti trong mu di dng t do, mt phn tham gia lin kt vi protein ca huyt thanh. T l tham gia lin kt vi protein ca cht c khc nhau c th dao ng t 1 99% ph thuc vo tnh cht l, ho hc ca chnh cc cht c T huyt thanh cc cht c th tan trong du m, cc cht khng ion ho nhanh chng xm nhp vo cc m, cc t bo ca cc c quan. Cc cht tan trong nc, cc cht c kh nng ion ho, cng nh cc cht phn cc xm nhp vo cc c quan, t chc chm hn. Tc xm nhp ca cc cht c cn ph thuc vo lng mu ti cho cc c quan , c bit mt s c quan c lng mu ti ng k: no, thn, tim ,phi...Cc c quan, t chc khc c lng mu ti t hn nn tc xm nhp ca cc cht c c chm hn. Cn lu c v m chim t l ln trng lng ca c th nn mt s cht c c th tch lu ng k trong c, cc cht c kh nng tan trong du m tp trung mt lng ng k trong m, c bit cc loi thuc ng, thuc m: ete, cloroform, cc loi thuc ng benzodiazepin, barbiturat...Tuy nhin, cn tu thuc tnh cht v chc nng ca cc c quan, t chc, tnh cht ca cc cht c m c s phn b khng ging nhau cc c quan, t chc: ru d tan nn c phn b trong hu ht cc c quan v ch yu lu thng trong mu. Cc thuc m, thuc ng tan trong du m nn n tp trung nhiu m thn kinh, gan , thn. Asen v cc kim loi nng c c gi li nhiu cc t chc sng: mng tay, mng chn, tc. Cc thuc tr su chor hu c tp trung cc t chc m, benzen tp trung tu, fluor rng, ruu methylic tp trung thn kinh th gic, digitalin tim.S phn b ca cc cht c ti cc c quan, t chc cn ph thuc vo tnh trng ng c cp tnh hay trng din. Khi ng c cp tnh thng thy ch gan, thn, nhng khi ng c trng din li thy tp trung tu, xng, tc.6.3. S chuyn ho ca cc cht c trong c th. Trong c th c s tc ng ca qu trnh sinh hc, cc cht c b bin i theo nhiu c ch khc ph thuc vo bn cht ca cht c. Cc cht c sau khi tri qua qu trnh bin i a s s bin thnh cht khng c hoc t c hn to iu kin thun li o thi ra ngoi. Tuy nhin c mt s cht, tnh c hi tng cao. Qu trnh chuyn ho ca cc cht c trong c th c th gp mt s dng nh sau:Thng thng, cac phan ng chuyn hoa cht c c chia lam hai pha:Chuyn hoa pha I: gm chu yu cac phan ng oxy hoa kh, thuy phn va hydrat hoa epoxid. Cac phan ng nay se tao ra mt nhom chc phn cc yu trn cu truc cac xennobiotics (cht t bn ngoai vao c th), co th lin hp c trong qua trinh chuyn hoa pha II6.3.1. Phan ng oxi ho: l dng thng thng nht ca phn ng chuyn ho sinh hc, gm oxi ho ru v adehyt thnh cc axit tng ng. Oxi ho cc alkyl thnh cc alcol, oxi ho cc hp cht lu hunh thnh sunfoxid v sunfone...S oxi ho chia thnh hai loi:- S oxi ho do gn oxi trc tip vo cacbon, nit, sunfur...- S oxi ho nh s kh hydroS oxi ho c th lm tng c tnh ca mt s cht, in hnh l s oxi ho alcol methylic thnh aldehyt formic hay l s oxi ho anenes (cc cht c nhn thm nh benzen). y c s gn oxi vo hai nguyn t cnh nhau trong mt vng hnh thnh gc epoxide. Cht ny rt khng bn c hot tnh cao hn cht ban u, c coi l tin gy ung th.Phan ng oxy hoa c xuc tac bi cac enzym cua microsom gan (monooxygenase), c bit la cytocrom P450 va monooxygenase cha flavinin hinh la phan ng chuyn hoa cua toluen

Cht chuyn hoa gy ung th6.3.2. Phan ng kh . t gp hn oxi ho, bao gm:- Aldehyt v cetone b kh thnh alcolCloral tricloretanolCCl3 -CHO CCl3-CH2OHCc nhm nitro (-NO2) ca cacbua thm c kh thnh amin (-NH2)Nitrobenzen PhenylhydroxylaminMt s nhom chc nh nitro, diazo, carbonyl, anken, disulfit, sulfoxidu co kha nng bi kh:Trong c th qu trnh oxy ho kh thng lin quan vi nhau v c thc hin nh h thng enzym oxy ho kh.

6.3.3. Phan ng thu phn. Vi s tham gia ca phn t nc i vi cc cht h c, qu trnh thu phn nh enzym, vi cc cht v c l phn ng ho hc thng thng. Thu phn cc hp cht cacbon, sulfur, nit v photphat thnh axit v ru. Cc nitril thm b thu phn thnh axit cacbonxilic tng ng, ngc li nitril mch thng ch yu chuyn thnh cyanide, do n c tnh c cao hn.Cac hp cht ester, amid, hydrazid va cacbamat u bi thuy phn bi nhiu loai enzym khac nhau. Vi du:+ Acetylcholin di tac dung cua cholinesterase chuyn thanh axit acetic va cholin.+ Atropin la ester cua axit tropic va tropanol

tho, huyt thanh va t bao gan co enzym thuy phn atropin thanh nhng cht koong c, cho cung co nhng yu hn, ngi khng co enzym nay. iu nay giai thich ly do c tinh cua atropin tng ln rt nhiu ngi so vi tho.Chuyn hoa pha IISan phm chuyn hoa pha I va cac xenobiotics cha nhom chc OH, amino, -COOH, halogen, epoxid co th tip tuc tham gia cac phan ng lin kt vi cac cht chuyn hoa ni sinh (ng, axit amin, glutathion, sulfat.), tao thanh cac san phm thng phn cc hn, it c hn va d ao thai hn cac cht c ban u. Tt ca phan ng pha II u cn nng lng va c chia thanh 2 nhom:Nhom 1: tac nhn lin hp c hoat hoa ri phan ng vi cht c (hoc cht chuyn hoa pha I).Nhom 2: cht c ((hoc cht chuyn hoa pha I) c hoat hoa ri lin hp vi 1 axit amin, chu yu la glycin.Phan ng lin hp c hai c tnh quan trng c bn trong kh c. l, nhn chung tr thnh cht t c hn nguyn u ca n (tr vi ngoi l) v d ng b o thi ra nc tiu.- Lin hp vi sulfat: san phm lin hp la cac ester sulfat tan trong nc va d dang bi ao thai ra khoi c th. Cht cho nhom sulfat la 3-phosphoadenosine-5-phosphosulfat (PAPS) c tng hp t phan ng sau:

- Lin hp glucuronic. Rt nhiu cht c o thi di dng lin hp vi axit glucuronic (do trong phn t axit glucuronic c nhm adehyt chuyn thnh dng bn axetal nn chng c th lin hp vi cc nhm hydroxyl ca cc cht khc nh ru, cc axit to cc ester): phenol v dn xut, alcaloid, steroidPhenol + axit glucuronic Axit phenylglucuronic- Lin hp vi glutathion: kh c tinh cua cac cht a in t (hydrocacbon thm, dn xut halogen cua hydrocacbon, epoxid)

- Lin hp vi nhm methyl: Cht cung cp nhm methyl cho phn ng lin hp l methionin, mt axit amin cn thit cho c th. Khi b ng c pyridin, qua phn ng methyl ho to ra methylhidroxypyrydin t c hnPyridin methylhidroxypyridinPhan ng methyl hoa xay ra trn cac nhom chc amino, hydroxyl hoc thiol vi cht cho nhom methyl la S-adenosyl methionin (SAM), c tao thanh t phan ng gia methionin va ATP

- Lin hp vi cac nhom thiol (-SH): mt vai cht c co th lin hp vi nhom thiol (cystin, cystein) gy ra s ri loan phan rng enzym va qua trinh oxy hoa kh cua t chc. V d cc kim loi nng, asen, thu ngn, axit hu c c halogen, benzen:R-SH + BrCH2- COONa HBr + R-S-CH2-COONaTrng hp ng c nay keo dai dn n s thiu cystein la mt axit amin cn thit cho s tng trng.- Lin hp vi lu hunh (s tao thanh thiocyanat). Axit v mui cyanua lin hp vi lu hunh to thnh thiocyanat khng c v c o thi theo nc tiuNaCN + NaSCN + Na2SO3Khi ng c axit cyanhydric (HCN) va cac dn xut nh NaCN, KCN, di tac dung cua enzym rhodanase, cac cht trn se kt hp vi thiosulfat tao thanh thiocyanat kem c hn cyanua 200 ln:CN- + S2O32- SCN- + SO32-- Lin hp vi H2SO4. Nh trng hp phenol lin hp vi axit sunfuric to thnh phenylsunfuric t c hn. Ni tit t Steroid v dn xut c o thi di dng lin hp sunfuric- Lin hp vi glycocol. cc hp cht c cha nhm chc cacbonxyl (-COOH ) c th phn ng vi nhm chc amin ca glycocol to ra cc hp cht t cC6H5-COOH + H2N-CH2-COOH C6H5CONH-CH2COOH (Axit hipuric)6.4. S o thi cht c. Cht c c o thi t nhin qua nhiu ng khc nhau.* o thi cc cht c qua thn. Thn ng vai tr ht sc quan trng trong qu trnh o thi cc cht c. Cht c c thi nguyn dng hoc ph bin hn di dng lin hp. Bng cch theo di nc tiu chng ta c th bit c ch tc dng ca cht c, phng php kh c ca c th. V th nc tiu thng c dng phn tch cht c.* o thi cc cht c qua ng tiu ho: l c quan o thi nhiu loi cht c. T c th cc cht c c chuyn qua gan, mt v nhanh chng ti rut ri c o thi qua phn ra ngoi.* o thi cc cht c qua ng h hp. B my h hp o thi mt s loi cht c, trong ch yu l loi kh c nh kh CO, H2S, HCN, Ru v thuc m...* o thi qua mt s tuyn ngoi tit. Mt s tuyn ngoi tit cng tham gia vo qu trnh o thi cht c: tuyn sa, tuyn m hi, tuyn nc bt...Tc o thi cc cht c ph thuc vo nhiu yu t: bn cht ca cc cht c, kh nng hot ng ca cc c quan, ph thuc vo mi trng chung quanh: nu cht c khng c tnh tch lu, cc c quan ca nn nhn hot ng tt, mi trng c ty ra th tc o thi cc cht c c thun li nhiu.7. CC NGUYN TC C BN CHN ON NG CChn on ng c c ngha quan trng trong thc t lm sng, gip tm ra c nguyn nhn, ra c cch thc, phng php x tr,cp cu v iu tr ng c7.1. Chn on lm sng. Da trn d kin tin s, cc kt qu quan st ti hin trng xy ra ng c, cc theo di lm sng i vi bnh nhn ng c. Chn on lm sng nhm pht hin ra cc triu chng in hnh, c trng ca cc cht c hoc nhm cc cht c tc dng vo c th hoc c quan t chc nht nh.Trong ng c xut hin cc ri lon tm thn, hn m, thao cung, cc du hiu tn thng no. Cc triu chng c trng cho cc cht hng thn kinh nh cc cht ma tu v c bit cc cht kch thch thn kinh trung ng nhm amphetamin, cc thuc gim au, gy nghin, ng c cc thuc ng barbituratChn on ng c da theo cc triu chng lm sng cn thn trng, nn xem xt theo nhiu hng, cc kha cnh khc nhau trnh nhng sai st, cn kt hp vi cc phng php khc trong chn on m bo chnh xc hn. Trong chn on lm sng cn xc nh c thi im, v tr cht c tc dng. Khng nh c cc d liu c th cho php khng nh c cc nguyn nhn gy ng c, t ra c cc bin php cp cu, iu tr.Khi bnh nhn trong trng thi hn m, th cc quan st ti hin trng xy ra ng c s gip rt nhiu trong chn on ng c. C th tm thy cc du hiu ca cc cht c li trong bao b, dng c cn li ti hin trng. Cc mu, vt thu ti hin trng ng c cn gi phn tch, xt nghim c th tm c cc nguyn nhn gy c, b sung cho cc du hiu lm sng7.2. Chn on bng cc thit b my mc. Cc my mc chuyn dng gip ch rt nhiu trong chn on ng c.* Phng php in no . Da vo s bin i in sinh hc ca no c th cho php chn on c mt s cht c, c bit l cc cht c thn kinh. Phng php ny thun li trong tnh trng hn m, khng cho php hi hoc khm lm sng, phng php c th tin lng c mc ng c* Phng php in tm . c dng chn on mt s trng hp ng c c bit vi cc cht c ti tim. Khi cc cht gy ng c i vi tim, gy mt s ri lon, c phn nh qua in tm .* Xc nh cc ch s v huyt hc. Mt s ch s v huyt hc cn c xt nghim gip cho chn on ng c: s lng hng cu, bch cu , tiu cu v cc ch s khc ca huyt hc.* Xc nh chc nng ca h h hp. Dng mt s phng tin xc nh chc nng ca h h hp c bnh thng khng, qua xt nghim c th chn on c mt s trng hp ng c, c th l cht c nh hng n h h hp.7.3. Tin hnh phn tch tm cc cht c. y l phng php quan trng chn on ng c. Da vo mu bnh phm ca bnh nhn, cc mu thu xy ra ni ng c, c tin hnh phn tch ti cc phng th nghim phn tch c cht tm cc nguyn nhn gy c. Tu iu kin ca trang thit b ca phng th nghim m c th tin hnh cc phn tch sau:* Cc phn ng c hiu: Da vo tnh cht l, ho hc ca cc cht, cc nhm cht c s cho phn ng vi cc thuc th c hiu. Da vo ta c th chn on c cc nguyn nhn gy ng c hoc cn tin hnh cc phn tch su khng nh* C th x dng cc phpng php phn tch cng c hin i phn tch mu vt cn xc nh cht c: phng php sc k lp mng, phng php quang ph hp th t ngoi, phng php quang ph hng ngoi, phng php quang ph hp th nguyn t, phng php in ho, phng php sc k kh, sc k hiu nng cao (HPLC) , phng php phn tch sinh hc (bioassay)...7.4. Chn on php y. Cn c vo gii phu t thi, da vo cc hu qu li ca cc cht c tc dng vo cc c quan, c th chn on c cc nguyn nhn gy ng c. chn on ng c trng din thng gp nhiu kh khn do c im cc du hiu ng c khng bng pht, khng d di, thng cc du hiu rt m nht...Cn phi kt hp nhiu phng php quan st t lm sng, cc xt nghim cn lm sng nh gi chc nng cc h c quan, c bit l cc nh gi trn cc my mc chuyn dng nh xt nghim cc ch s sinh ho, in no , nh gi chc nng h hp... a ra kt lun chnh xc.8. CC PHNG PHP CP CU V IU TR NG CKhi xy ra ng c cp tnh phi nhanh chng t chc cp cu chng c. Cc phng php iu tr nhm mc ch:- Loi b cht c ra khi c th- Ph hu hoc trung ho cht c- iu tr cc hu qu ca ng ciu tr cc triu chng ng c, nng cao sc khng ca c th l bin php quan trng nht v bao gi cng p dng trc tin.8.1. Loi b cht c ra khi c th. Vic loi b cht c ra khi c th c th c thc hin qua cc con ng: tiu ho, tit niu, qua phi v qua thn8.1.1. Phng php loi b cht c qua ng tiu ho. Hiu qu ca phng php ny ph thuc nhiu vo thi gian hp thu, ph thuc vo cht c...nhng nn tch cc loi cht c qua ng ny nu khng c cc chng ch nh c th.- Gy nn: Nu khng c cc chng ch mh nh ung phi cht n da, ng c stricnin, xng du hoc bnh nhn hn m su... th phi gy nn. Trng hp bnh nhn hn m, mun gy nn cn t ng xng bo v ng h hp, chng sc v dch nn khng lt qua ng th. Gy nn bng kch thch hng, tim di da apmcphin: 5-10 mg, hoc ung 1,2 g bt ipeca ho trong mt t nc m.- Ra d dy: nu khng gy nn c th phi ra d dy. Nn ra d dy trong 3 gi u sau khi ng c hn ch vic hp thu vo mu. Khi ra ly 250-300ml dich ra u tin phn tich xc nh cht c. Dung dch ra d dy c th l:+ Dung dch kali permanganat 1-2 %; l cht oxy ho phn ng d vi cc cht hu c, sa long, huyt thanh mn ng trng + Dung dch magnesium oxid hoc magnesium hydroxid trung ho axt dung nng 2,5% (tnh cho MgO) + Dung dch Natri hydrocacbonat 0,5% (nu ng c bng axt th khng dng v gii phng kh CO gy trng bng, thng d dy) Nhng bnh nhn ng c v axt hoc base mnh, strychnin, ung phi cht du hoc phi hn m su th khng ra d dy.-Dng thuc ty. S dng loi nh nh: natri sunfat, magnesium. It khi dng du ty v nguy him trong trng hp ng c photpho, santonin, DDT, photpho hu c hoc nhng cht c tan trong du.-Tht tho. Mc ch ca tht tho l ra i trng; thng ra bng dung dich NaCl 0,9%.8.1.2. Loi b cht c qua thn. Nhiu cht c sau khi vo mu c o thi qua nc tiu. thc y qu trnh ny ngi ta c th:- Truyn dch: c th cho dung dch u trng, thuc li niu (nu khng b bnh thn). Ch l khi i nhiu c th mt cht in gii Na+, K+, Cl-,... cn b p thch ng.Mt s cht c c c tnh axit yu thng o thi nhanh chng trong mi trng kim (bacbiturat) hoc gim tc dng mi trng kim (photpho hu c); nn ngi ta thng a dung dch kim vo c th nhng cn theo di pH ca mu khng vt qu 7,6, v nu kim qu s c ch h hp. Mt s cht c gim tc dng trong mi trng axit nhng trong lm sng gim pH ca mu d gy bin chng nn t p dng iu tr.- Nu c iu kin v xt thy bnh nng, ngi ta dng phng php lc mu bng thn nhn to.8.1.3. Thay mu. Phng phnp ny p dng trong trng hp ng c qu nng, ng c cc cht gy tan huyt qu nhiu hoc gy methemoglobin qu nng rt kh c th hi phc, cc trng hp khng th gii quyt c bng phng php lc ngoi thn...nh ng c cc nm c, do rn cn, ng c aminazin rt nng8.1.4. Qua ng h hp. Mt s cht c th kh hoc th bay hi c th loi nhanh chng ra khi c th bng ng h hp. ngi bnh ni thongv lm h hp nhn to (tr trng hp ng c cc cht gy ph phi: phosgen, clor, SO2...). C iu kin dng my tr h hp nng oxi 50%8.2. Ph hu hoc trung ho cht c. y l phng php dng cc cht chng c ph hu hoc trung ho cc cht c theo cc c ch khc nhau da vo tnh cht vt l, tnh cht ho hc hoc ho sinh...8.2.1. Chng c da vo tnh cht vt l. Dng cc cht c kh nng hp th cc cht c nh cho ung 1-2 tha canh than hot tnh. Than hot tnh c th hp phu nhiu cht c nh aconit, atropin. nicotin, barbiturat, digitalin, nhiu kim loi nng. C th dung c kaolin.8.2.2. Chng c da vo tnh cht ho hc. C th dng cc cht gy nn, cc cht ra d dy, tht tho, hoc dng ngay sau khi gy nn, sau khi ra d dy, tht tho. C th s dng hai loi sau:* Cc chng c a nng: l cc cht chng c c kh nng dng vi nhiu loi c, to nn nhng cht khng tan hoc t tan:- Lng trng trng (thng iu ch bng cch ho tan 6 lng trng trng vo thnh 1 lt nc, c th thm cht thm cho d ung) : dng chng ng c cc kim loi nng, do albumin trong lng trng trng tc dng vi kim loi nng to anbuminat khng tan- Dung dch tanin: rt cng hiu kt ta kim loi nng, cc alcaloid. Alcaloid to vi tanin hp cht tanat kt ta nhng tan trong axit clohydric ca d dy. Do tanin ch lm chm tc dng ca cht c; sau khi ung thuc gii c phi gy nn- Dung dch chng c vn nng ca Jeanel (Php) rt cng hiu, gm hai dung dch:Dung dc A: St (II) sunfat 139gNc ct700mlDung dch B: Natri sunfit110 gMangesium oxid 22 gNc ct660 mlTrn hai dung dch khi dng, s to ra st (II) sunfit, mangesium, natri sunfat, st (II) hydroxid v mt t mangesium oxid tha. Mi ln ung vi tha canh, ung nhiu ln hoc tng nhm cht nht nh. u im l dng cp rt cng hiu qu, song cn c s chn on nguyn nhn gy ng c chnh xc:- Dung dch ng vi chng ng c axit oxalic, phenol- Dung dch natri sunfat v mangesium sunfat chng ng c ch, bari- Dung dch axit boric, nc chanh (axit citric), axit tactric hay axit sunfuric chng ng c kim- Dung dch natri thiosunfat 3% chng ng c HCN- Dung dch atropin sunfat cho ng c thuc tr su ln hu c- Dung dch BAL chng ng c kim loi nng (to phc bn do c hai nhm -SH)-Dung dch Trion B cng l cht to phc tt vi nhiu kim loi nn c dng gii c. Tuy vy khi dng d lm mt nhiu ion Ca2+ ca c th, nn ngi ta s dng mui canxi ca Trilon B. V d: Calcitetracemat, ng 10 ml dung dch 5%. Ngy truyn 1-2 ng nh git tnh mch vi huyt thanh (ngt hoc mn ) ng trng. Mi t dng 3-5 ngy. Sau khi ngh 4-7 ngy c th dng mt t na.8.3. iu tr triu chng c. Trong iu tr ng c cp, mt mt v cha bit ngay cht c no (ang ch kt qu phn tch ), mt khc, cht chng c khng nhiu, ngi bnh c th b e do tnh mng v cc ri loi chc phn. V vy iu tr triu chng c vai tr rt quan trng. Ngi ta thng s dng hai cch:8.3.1. iu tr i khng. Dng cc cht c tc dng dc l i lp nhau: ng c strichnin dng barbiturat, ng c phospho hu c dng atropin, dng neostigmin chng lit c do cc hp cht cura gy nn bnh nhn khi cht v lit c h hp).Cc cht i khng theo c ch min dch: cc nhm cht ny c dng nhiu trong cc trng hp ng c do cc ng vt nh rn hoc cn trng, di dng huyt thanh khng c8.3.2. iu tr triu chng. Nu bnh nhn ngt cn lm h hp nhn to, cho th oxi hoc cacbogen. Trng hp ng c bi clor, brom, photgen, SO2...khng lm h hp nhn to. Nu bi ngt do t lit men phi dng xanh methylen hoc glutation, chng s phn ng vi nc v cung cp oxi cho c th:Xanh methylen + H2O Lecobase + 1/2 O2R-S-S-R + H2O RSH + 1/2 O2Sau khi lm h hp nhn to c th dng thuc kch thch thn kinh trung ng:- Ephedrin tim bp 1-2 ml dung dch 3%- Amphetamin: tim tnh mch 0,01-0,02g- Theophylin ho tan: tim tnh mch hoc di da 0,25g x 3 ln/24 gi- Lobelin dung dch 1% tim tnh mch ti a 0,1 g mt ngy* Chng tru tim mch: tim cc cht tr tim nh dn xut ca camphor, spartein, niketamid.* Chng ri lon nc, in gii v toan kim: chng mt nc v cht in gii bng cch truyn dung dch glucose 5% v dung dch NaCl. trng hp nc (gim protid mu v Na+ trong huyt tng) th khng dng dung dch NaCl, dng n thun glucose.iu chnh toan kim bng cc thuc sau:- Nu tha kim dng thuc li niu nhm Fonurit nh acetazolamid thi kim ra nc tiu, hoc b toan bng cch truyn dung dch NH4Cl 8,3%- Nu toan huyt th truyn dung dch NaHCO3 15%* Chng bin chng mu- Vi cht c nhm nitrit to methemoglobin dng xanh methylen: tim tnh mch 5-40 ml dung dch 1%- Trng hp ng c lm mu chm ng th truyn tiu cu hoc mu ti, cho thm thuc nhm cocticoid (v d tim tnh mch depersolon).Tm li vic cp cu ng c nng l phi iu tr ton din bng h hp, tun hon, thn kinh,...ng thi p dng cc thuc gii c c hiu.9. PHN LOI C CHTC nhiu cch phn loi cht c. Trong ho hc, ngi ta thng da vo cu trc hoc tnh cht vt l, ho hc ca chng phn loi. Trong kim nghim c cht, vic phn lp cht c ra khi mth l bt but xc nh s c mt ca cht c. V vy hu ht cc tc gi da vo phng php phn lp cht c phn loi cht c. Theo Svaicova, cht c c chia lm 6 nhm.9.1. Nhm cht c phn lp bng phng php ct bay hi. Nhm ny c cc cht c hu c bay hi nh ru, alehye, cetone, HCN v cyanogen...9.2. Nhm cht c phn lp bng cn, axit. Nhm ny bao gm phn ln cc cht hu c thng gp. phn lp cht c, dng cn 950 cho vo mu th axit ho bng axit hu c. y c th phn lp c cc cht mang tnh base nh alcaloid v base tng hp.9.3. Nhm cht c phn lp bng cch chit thng vi dung mi hu c. Bao gm phn ln cc cht c tr su dit c.9.4. Nhm cht c phn lp bng cch v c ho mu th. Nhm ny gm cc kim loi c nh arsenic, thu ngn, ch...9.5. Nhm cht c phn lp bng phng php thm tch (dialyse). Nhm ny gm cc anion c.9.6. Nhm cht c phn lp bng phng php c bit. Khng thuc nm nhm trn nh photphua, silico-fluor.Theo Stolman v Stewart, cht c c phan loi thnh 5 nhm:- Cc kh c v hi c- Cc cht chit c bng dung mi hu c t dung dch nc axit- Cc cht chit c bng dung mi hu c t dung dch nc kim- Cc kim loi c- Cc cht c bay hi./.

CC PHNG PHP PHN TCH CHT C

MC TIUNu c cc giai on ca qu trnh phn tch cht c.Trnh by c phng php phn lp chung ca cht c v c, hu c.Chn c phng php phn lp thch hp cho cc cht c thng gp.

Kim nghim c cht c mt s c im ch yu sau:* Mu th rt phong ph a dng* Cn phn lp mt lng nh cht nghi vn l cht c, t mt lng mu th kh ln c thnh phn phc tp* Cc cht c trong c th, trong mi trng thng khng gi nguyn cu trc, thnh phn m b bin i, chuyn ho....V vy thng phi phn tch mt hn hp gm cht c v cc sn phm chuyn ho hoc phn hu ca n.* Cn phi nh gi ng kt qu kim nghim. Nhiu cht c th gp trong qu trnh phn tch mu th l thnh phn t nhin ca c th. Do vy, kim nghim c cht c giao cho dc s, l ngi c hiu bit nht nh v y hc, ho hc.1. YU CU V THIT BI V THUC TH TRONG C CHT HOC* Ngoi yu cu chung ca mt phng th nghim ho hc, phng th nghim kim nghim c cht cn thm mt s trang b sau:- T ht gi ht cht c, bo v sc kho- T lnh bo qun mu th v ho cht d b nhit phn hu- Cc dng c c bit nh ct phn on ct ru* Thuc th v dng c- Cc ho cht phi tuyt i dng loi P.A- Dng c phi tuyt i dng sch- Nc ct hai ln (phi ct trong b t bng thch anh) ng trong bnh kn bng polyethylen2. KIM TRA S BMU THTrc khi bt u kim nghim mu th, nu khng c ch nh c th th kim nghim vin cn th s b trc nh hng. D nhin kt qu th s b khng th thay th cho kt lun chnh thc. Mt khc, khng nn nhng php th s b mt qu nhiu mu th. Th s b c th gm nhng ni dung sau:2.1. Nhn xt v tnh cht, c im ca mu th. Mu sc ca mu th c th gi cho ta ngh ti cht c. V d mu vng ca axit picric, acridin, mu xanh ca mui ng v cht mu ca anilin, mu tm ca KMnO4Nu mu th l cc nim mc c mu en chng t axit v c mnh nh axit sunfuricMi ca mu th c th gip ch cho kim nghim vin, v nhiu cht c c mi mnh. V d mi hnh nhn c lin quan n axit cyanhydric, axit nitrobenzoic. aldehyt benzoic, mi ru, mi phenol...Nu mu th lu c mi thi s cn tr nhiu n vic nhn xt mi.2.2. Kim tra s c mt ca cht bo qun. Nu mu th l ph tng, c quan hoc t chc ngi, ng vt th trnh thi ra do nh hng ca nhit ngi ta thng cho thm cht bo qun.Thng dng nht l ru ethylic. Ngoi ra c th bo qun bng focmol, phenol, glycerin. Nu th c ru th loi tr cch xc nh ru, mt khc, phi loi tr ru trc khi v c ho xc nh kim loi. Cn focmol cn tr nhiu n vic kim nghim khc v n l cht kh kh mnh. N c th lin kt vi cyanur, cc hp cht nhm -NH2. Focmol cn tr tm ru methylic khi dng phn ng oxi ho ru thnh focmol.2.3. Quan st k cc vt l trn mu th. C th quan st bng mt thng hoc knh lp xem c vt l khng. V d tinh th nh mnh s v ca As2O3, tinh th hnh lng tr ca strychnin nitrat, cc mnh l c, nm c, cc ht thc vt....Nhiu khi ngi ta ly ring nhng vt l dng knh hin vi quan st hnh dng, cc t chc c bit, nht l mu th c cc phn tho mc.2.4. Th pH ca mi trng. Vic xem xt pH ca mi trng gip cho kim nghim vin m rng hoc thu hp khi lng cng vic phi kim nghim. Mun th pH th ly mt t mu th ho tan vo nc xong dng giy qu kim tra. Nu mu th c phn ng axit th c th c axit hu c do c th to ra, c axit t do hoc mui ca axit mnh, mui ca kim loi nng. Trong trng hp ny c th thm vi ch th khc xem xt mc axit ca mu th. C th dng giy congo hoc giy ch th vn nng. Nu giy congo chuyn sang xanh th trong mu th c axit v c hoc axit hu c nng ln t ngoi a vo. Nu mu th c tnh kim th c th cc mui kim nh cacbonat, silicat, kim t do (sn phm ln men ca mu th ngun gc ng vt sinh vt cng to ra amoniac v H2S) hoc mui kim d thu phn ca axit yu NaNO2, KCN... th s b amoniac v H2S ta ly mt t mu th cho vo ng nghim v dng 3 loi mu th t ln ming ng nghim: giy qu thm t, giy tm acetat ch v giy tm ng sunfat. Sau khi un nh ta thy:- Giy qu chuyn mu xanh, giy tm ng sunfat cng c mu xanh, cn giy tm acetat ch khng mu th c th c amoniac a t ngoi mu th vo.- Giy qu v giy tm ng sunfat c mu xanh, giy tm acetat ch c mu nu hoc en th trong mu th c amoniac v H2S do qu trnh ln men to ra. Trong trng hp ny khng th t ra vn kim nghim amoniac.2.5. Th s b cc cht c bay hi. Dng 5-10 g mu th (nu cn th nghin nh) cho vo bnh nn v axit nh bng HCl, y kn bng nt c nh cc loi tm dung dch bc nitrat, ng sunfat v benzidin, ch acetat v thu ngn (II) clorua. un cch thu nh 60-700C. Nu:- Giy bc nitrat en, giy thu ngn (II) clorua vng, giy ch acetat khng mu th mu th c th c kh H3As, H3P.- Giy bc nitrat en, giy thu ngn (II) clorua vng, giy ch acetat en th c th c cc kh trn cng vi kh H2S.- Giy ng sunfat v benzidin c mu xanh c th c HCN. trong trng hp ny c th gn thm giy tm dung dch axit picric trong kim, nu c HCN giy ny chuyn sang mu hng tm.Th s b ny c gi tr tuyt i v mt m tnh.2.6. Th s b asen bng nghim php Riench. Ly khong 20 g mu th, thm vo 50 ml dung dch HCl 18%, tt c cho vo bnh nn 100 ml. Cho vo vi vng ng ra bng axit nitric long. un nng bnh 30 pht, sau un cch thu 30 pht na. Nu c lng arsen th trn vng ng c mt lp kim loi xm. Ly vng ng ra sch bng ru ethylic v ether. ether bay hi ht, cho vng ng vo ng thu tinh hn kn mt u, un nh v lm lnh bng mu giy lc thm t. Khi c arsenic trong mu th phn lm lnh ca ng thu tinh c mt vng trng, a vo knh hin vi s thy nhng tinh th c bit.2.7. Th s b thu ngn bng nghim php Riench. Lm ging nh trng hp th arsenic nhng vng ng tip xc vi dung dch th nhit thng trong 24 gi. Sau ly ra ra sch bng ru ethylic v ether. Sau khi cho bay hi ht dung mi, cho vng ng vo ng thu tinh c cha t tinh th iode. Hn kn mt u ng v un nh. nu c thu ngn s c vng tinh th HgI2 mu bm vng thu tinh, soi knh hin vi s thy tinh th hnh qu trm c bit.Trong hai nghim php Riench th s b arsenic v thu ngn, vic xut hin vng hp cht xm hay en, th cha th chng minh ngay c l arsenic hay thu ngn, v mt s kim loi khc nh bismut, antimon, cadmi cng c vt tng t. Do vy cn phi t thng hoa v soi tinh th.2.8. Th s b alcaloid v mt s base hu c c phn ng ging alcaloid. Ly khong 40-50 ml nc tiu, nc d dy em i kim ho bng amoniac (phn ng vi giy qu), chit bng ether 3 ln. em dch cht bc hi n kh v th phn ng ca alcaloid vi thuc th Dragendorff hoc Munier-Machbeuf. nu phn ng dng tnh l c alcaloid hoc base hu c tng hp: dn xut phenothiazin, dn xut pyradon (antipyrin, pyramydon)...Mun xc nh c th hn cn phi dng cc phn ng c hiu.2.9. Th s b mt s cht c hu c chit mi trng axit. Cch chit: ly mt lng mu th thch hp, axit ho n pH = 4,5 v lc mnh vi ng th tch ether hoc chloroform. sau khi tch lp, rt pha dung mi, bay hi n kh v lm phn ng mt s cht:- Bacbiturat: dng phn ng Parris: to thnh phc hn hp c mu hng vi coban nitrat v diethylamin trong mi trng methanol (cho vi git dung dch bacbiturat trong ether ln mt bng giy lc. kh thm vi git coban nitrat 3% trong methanol. sau khi giy kh ln ming l ng amoniac s c mu hng)- Thuc tr su photpho hu c: dng phn ng c ch enzym cholinesterase- Salicylat v dn xut (salaid, aspirin) dng phn ng vi dung dch FeCl3 5% (vi aspirin cn thu phn mi trng kim trc khi th) cho mu tm.- cc nitrophenol (mon, dinitriphenol, dinitro O-cresol...) em kh ho bng km trong mi trng axit chlohydric. Thm FeCl3 5% s c mu .3. PHNG PHP CHUNG TRONG KIM NGHIM CHT CMu ca kim nghim cht c rt phc tp v hm lng cht c trong mu t, nn phi chn cc phng php kim nghim cht c thch hp c th phn lp v xc nh cht c mt cch chnh xc v t tn km.C th chia qu trnh phn tch cht c thnh ba bc ch yu sau: Chit xut cht c (extraction). Phn tch (separation): vi cc phng php sc k. Xc nh cht c (identification): thng dng cc k thut o ph.3.1.Chit xut cht c (Extraction)Chn dung mi thch hp chit cht c khi mu, t l s dng thng l 5-25 th tch dung mi cho 1 th tch cht c. C th dng mt hay phi kt hp nhiu k thut chit tu vo c tnh l ho ca cht c trong mu.Cc k thut chit thng s dng l: Xay vi dung mi (blending). Lc vi dung mi (shaking). Chit soxhlet. Chit xut lng siu ti hn (supercritical fluid extraction).3.1.1.Xay vi dung mi (blending)Thng p dng nht trong trng hp cc mu cha cht c l t chc, m hay thc n cha cht c.Tin hnh: cho mu v dung mi vo my xay, xay trong 5-15 pht. Ly phn dung mi ho tan cht c ra.3.1.2. Lc vi dung mi (shaking)C th dng my lc hay lc tay. Phng php ny c u im l c th chit (lc) trong thi gian di (24 gi).3.1.3.Chit soxhletChit soxhlet, c th dng mt dung mi hay hn hp dung mi chit. Nguyn tc l dng mt lng dung mi nht nh qua h thng hi lu ly ht cc cht cn thit.3.1.4.Chit xut long siu ti hn (supercritical fluid extraction)Dung mi chit khi thay i iu kin p sut nhit si s thay i. Dung mi trong mt iu kin kt hp c p sut v nhit t trng thi trn nhit ti hn, trng thi ny dung mi va th hin c tnh ca c dng lng v kh. Khi dung mi s xm nhp vo mu nh di dng kh, nhng c c im ho tan nh mt cht long.CO2 thng c la chn cho chit xut siu ti hn.3.2.Tch cht c (separation)Tt c cc k thut sc k u c th c chn s dng tch cht c.Cc k thut sc k nh: Sc k lp mong (TLC). Sc k ct (ct hp ph hay ct trao i ion). Sc k kh (GLC). Sc k long hiu nng cao (HPLC). in di mao qun (CE).3.3. Xc nh (identification) xc nh cht c phng php c dng phn ln l o ph. Cc phng php o ph thng s dng l: Bng 1.1. ng dng ca cc k thut quang phQuang php dng

Ph UV-VisThng dng d nh lng

Ph qunh quangThng nhy hn vi nng thp hn UV-Vis

Ph hng ngoi (IR) v RamanDng trong phng php du vn tay

Quang ph ngn laDng nh tnh hay nh lng kim loi, kim loi nng.

Ph cng hng t ht nhn (MNR)c ng cho hu ht cht hu c

Khi ph (MS)Dng xc nh v nh lng v ph ny thng dng kt hp sc k kh v long

4. Ly mu, bao quan mu cho qua trinh phn tich4.1. Nc tiuMu nc tiu rt cn thit cho qu trnh phn tch cht c v th tch mu ln v nng cht c trong mu nc tiu thng cao hn trong mu. S hin din ca thnh phn chuyn ho ca cht c trong mu nc tiu cng gip cho nh danh cht c. Mu c ly khong 50ml (i vi ngi ln) v khng thm cht bo qun. Mu nc tiu c ly cng sm cng tt, c bit l trc khi bnh nhn c s dng thuc iu tr.4.2. Dch d dyMu dch d dy c th c do bnh nhn nn i hay t dch ht ra d d. Khi ly mu dch d dy cn ly phn u ca dch ra d dy, v phn sau thng nng cht c b long. Th tch mu khong 20ml v khng c cht bo qun. Mu dch d dy cha nhiu thc n nn phn b cht c thng khng ng u, nn cn phi tin hnh lc hay ly tm trc khi phn tch. Mu khi c ly sm c th cha lng ln cht c v thng khng c cht chuyn ho ca n.4.3. MuMu mu, huyt tng hay huyt thanh u c s dng trong phn tch nh lng cht c. Trong trng hp cht c l carbon monoxid hay cyanid th mu mu cn cho nh lng l mu mu ton phn (gm c huyt tng v huyt cu), ngi ln, mu c ly khong l0ml v c ng trong ng c cho heparin. Thng thng khng c s khc bit gia nng cht c trong huyt tng hay huyt thanh. Tuy nhin nu cht c khng phn b trong hng cu th mu mu b huyt gii lm long nng cht c. bnh nhn nghi ng ng c CO, khi ly mu trnh khong khng kh trong ng pha trn mu.5. MT S PHNG PHP PHN LP V XC NH CC CHT C V Cc tnh ca cht c hu c thng th hin bng c phn t ch khng ring thnh phn cc nguyn t to nn n, thm ch khi thay i mt gc hay nhm chc no ca phn t cng lm gim c tnh hay ngc li.i vi cc cht c v c th ngc li. C nguyn t v c ln mui ca n u mang tnh c. Cho nn khi xc nh yu t gy c, ch cn xc nh nguyn t gy c khng cn phi xc nh c hp cht ca n.Cc cht c v c gm mt s kim loi nh: As, Hg, Bi, Cu, Pb, Zn, Mn, Cr, Ni, Co, Ba,... Mt s gc acid c nh: nitrit, florua, oxalat, clorat, cc acid v kim mnh.Tu theo phng php phn lp cc cht c v c t cc mu th hu c ngi ta chia n thnh ba nhm chnh: Cc cht c v c c phn lp bng phng php v c ho: cc kim loi. Cc cht c v c c phn lp bng phng php thm tch: cc anion c. Cc cht c v c c phn lp bng phng php c bit.5.1. Phng php v c hoCc mui kim loi nng c kh nng lin kt protein ng vt hay thc vt to nhng hp cht bn vng kiu albuminat, cc albuminat kim loi khng phn ly nn khng xc nh c kim loi nu khng tin hnh v c ho.V c ho l qu trnh t chy cht hu c gii phng kim loi di dng ion. V c ho i khi khng i ti t chy hon ton cht hu c thnh H20, CO2 v cc cht n gin khc m ch c mc ch to cc hp cht n gin hn, km bn vng hn c kh nng d dng b ph hu tip tc.Cc phng php v c ho ph bin l: V c ho kh. V c ho t.5.1.1. Phng php v c ho kh v c ho theo phng php ny ngi ta un mu th vi mt s mui c tnh oxy ho dng bt nh KNO3, NH4NO3 hay c th tin hnh t n gin.Phng php t n gin: phng php ny dng xc nh s c mt ca cc mui ca Bi, Zn, Cu, Mn, .... nhng ngy nay t dng.Phng php t vi hn hp Na2CO3 v NaNO3: phng php ny t c s dng v ch thc hin c vi lng mu th nh t 5-10g. Mt s kim loi khi t nhit cao s bay mt nh Hg. Phng php ny thng dng tm asen trong nc tiu, tc, mng tay ...5.1.2. Phng php v c ho tPhng php v c ho bng clo mi sinh (HCl + KClO3)Nguyn tc:KClO3 + 6 HCl KC1 + 3 Cl2 + 3 H2O C12 + H2O 2 HCl + [O]Oxy nguyn t sinh ra trong phn ng s ph hu cht hu c chuyn n thnh H2O v CO2. Cc kim loi s dng mui clorid. Nhc im:Thi gian t tng i lu, nht l thi gian ui kh Clo.V c ho khng c hon ton.Gy mt mt mt s kim loi: As, Hg, Pb, Cu.Phng php ny trong thc t t c s dng.Phng php v c ho bng hn hp H2SO4 v HNO3Nguyn tc:H2SO4->H2SO3+[O]H2SO3->SO2 + H2OHNO3->H2O + 2 NO+ 3 [O]NO->N2 + 2 [O]Vai tr ca acid H2SO4v HNO3 l oxy hocc cht hu c. u tin acid H2SO4 c th nng oxy ho thp nhng sau mu th b mt nc nn nhit si ca hn hp tng ln v lm tng tc dng oxy ho ca H2SO4. u im:Thi gian ph hu hon ton cht hu c tng i nhanh.t nhy cao i vi nhiu cation so vi mt s phng php v c ho khc. Th tch dch v c ho thu c tng i nh. Nhc im: Lm mt mt lng ng k thu ngn.V c ho bng hn hp acid H2SO4, NHO3 v HClO4Nguyn tc:H2SO4 SO2 + H2O22 HNO32 NO2 + H2022 HCIO4 C1206 + H202Hin nay phng php ny c s dng rng ri cng vi phng php sulfonitric, Tc dng ca acid percloric tc dng ch yu giai on cui ca qu trnh v c ho. Khi nhit ln cao (203C) acid percloric lm tng th oxy ho ph hu cht hu c. u im:Oxy ho c gn nh hon ton cht hu c (99%).Tn t tc nhn oxy ho.Rt ngn c 2,5 - 3 ln thi gian so vi phng php sulfonitric.Th tch dch v c ho nh. Nhc im:Lm mt mt lng ln thu ngn.Phng php dng H2SO4 v H2O2Nguyn tc:2H2O2 02 + 2H2OPhng php ny cng c u im nh cc phng php trn v u im hn l t to kh c.Phng php dng H2SO4 v NH4NO3Amoni nitrat trong acid sulfuric cng to thnh acid nitric. Phng php ny gy nguy him cho ngi lm vic.6. Phng php lc v thm tch phn lp cc anionCc cht phn lp bng phng php lc hay thm tch gm: Cc acid v c: acid nitric, acid sulfuric, acid clohydric. Cc kim: natri hydroxid, kali hydroxid, amoni hydroxid. Cc anion c: nitrit, nitrat, oxalat, borat,...Phng php lc n gin: khuy u mu th vi nc ct, yn 2 gi ri lc. Dng acid tricloacetic loi protein v lc mt ln na. Dch lc dng lm cc phn ng tm anion c.Phng php dng mng bn thm: mng ny ch cho cc anion i qua.7. Cc phng php xc nh cht c kim loiC nhiu phng php xc nh kim loi. Trong kim nghim c cht thng s dng cc phng php vi lng, v kim loi c trong cc mu thng rt nh. Cc phng php c dng nh: phng php ho hc, phng php to phc mu vi thuc th hu c ri chit o quang, sc k, quang ph, quang ph hp th nguyn t ...8. MT S PHNG PHP PHN LP V XC NH CC CHT C HU CCc phng php dng phn lp cht c hu c: Phng php ct ko theo hi nc (dng cho cc cht c .d bay hi). Phng php chit xut vi dung mi hu c. Cc phng php c bit khc.Theo phng php phn lp, cc cht c hu c c phn loi thnh: Cc cht d bay hi phn lp bng phng php ct: ethanol, cyanua, aldehyd, ceton, cloralhydrat, phenol, hydrocarbon, ... Cc cht c phn lp bng phng php chit vi dung mi hu c km phn cc pH acid:barbituric, acid oxalic, acid salicylic, glycozid,... Cc cht c phn lp bng phng php chit vi dung mi hu c km phn cc pH kim: alcaloid, dn xut phenothiazin, amphetamin v mt s cht gy o gic Cc cht c phn lp bng cc k thut sc k kh: thuc tr su,8.1. Phng php ctDng c ct ko hi nc gm 3 phn chnh: Bnh sinh hi nc. Bnh ng mu th. ng sinh hn v bnh hng dch ct.Mu th c xay nh cho vo bnh, thm nc ct c hn hp st. Acid ho mu bng acid tartric hay acid oxalic 10%. Trnh acid ho mu bng acid v c v chng c th ph ;hu mt s cht c, v d nh acid cyanhydric b ph hu trong mi trng H2SO4.Ly dch ct xc nh cyanua, etanol, cloralhydrat, tetraclorua carbon, phenol,...8.2. Phng php chit xut vi dung mi hu c km phn ccChn dung mi hu c c h s phn b K (K = CNc/ CDung mi) cng nh cng tt. Cc dung mi hu c thng dng l: Ether, ether du ho: t to nh tng vi nc, d bay hi, khng lm h hot cht, d gy chy v n. Chloroform: l dung mi tt ca nhiu cht hu c nhng li d gy nh tng. Cc dung mi khc nh acetatetyl, benzen, cn amylic ... t dng.Phng php chit Chit vi dung mi hu c km phn cc pH acid gm:+ Nhom salicylat gm etylsalicylic (aspirin), methyl salicylat, acid salicylic.+ Nhom barbiturat: phnobarbital, barbiturat, amobarbital...+ Cc cht khc nh: acid oxalic, pheriol, mefenamic acid, cc glycozid,...+ Nhom benzodiazepin. Chit vi dng mi hu c km phn cc pH kimGm cc thuc nh: thuc nhom opioid (codein, dextropropoxyphen, methadon, morphin, pethidin, fentanyl), cocain, atropine, aconitin, khng st rt (cloroquin v quinin), strychnine, amphetamine v mt s cht gy o gic, nhm phenothiazin (clopromazin, promethazin, thioridazin...), nhm chng trm cm ba vng (imipramin, trimipramin, amitriptylin...), khng histamin (eyclizin v diphaenhydramin), mt s thc tim mch (lidocain, propranolon, verapamil, quinidin).8.3. Mt s phng php chit xut cht c bng dung mi hu cPhng php Stass - Otto - Ogier (S.O.O)Phng php Stass nguyn thuPhng php ny do Stass, mt nh c cht hc ngi B ngh nm 1850, ch yu phn lp cc alcaloid t ph tng. Sau phng php ny c Otto v Ogier ci tin cho hon chnh thm. Phng php nguyn thu c hai giai on:X l mu: Stass dng cn tch cc alcaloid ra khoi protein, cn c nhiu u im nh tnh tr v ho hc, tinh khit, tan trong nc, c kh nng tan cao, c th loi d dng bng s chng ct, c th kt ta protein. Stass acid ho mu bng acid tartric alcaloid dng tartrat alcaloid d tan trong cn hn. Ngoi ra cn cn c tc dng gy ta protein trong mu ph tng. Lc loi b protein ta c dung dch cn cha tartrat alcaloid. Chng ct dch chit cn p sut thp loi cn.Chit bng dung mi hu c: dch ct c kim ho bng KHCO3 hay NaHCO3 (dng kim yu v kim mnh s lm ho tan cc alcaloid c nhn phenol nh morphin do to morphinat, hay thu phn cc alcaloid c nhm ester nh atropin, cocain). Chit kit dung dch trn bng ete. Bc hi ete v lm cc phn ng xc nh alcaloid trn cn ete.Nhng hn ch ca phng php Stass v phng php ci tinS chit kit dung dch alcaloid bng ete lm ho tan cht m, cht mu v cht nha. Nhng cht ny khng c kt ta hon ton bng cn v c tm thy trong cn sau khi bc hi ete, s che lp phn ng tm alcaloid. Otto ngh chit xut dch alcaloid bng ete trc khi kim ho, khi cc tp cht trn s c loi bo.S kt ta protein khng hon ton v trong m ph tng c n 78% l nc. Do , khi cho cn vo ta s c hn hp cn - nc c cn thp khng th kt ta hon ton protein. Ogier ngh kt ta nhiu ln vi cn ngy cng tng bng cch chng ct hn hp cn nc trong chn khng nhit thp loi bt cn v nc, c mt hn hp st nh sir. Khi cho thm cn vo th mt phn protein na c ta thm, lc. Dch lc c c c nh trn v kh protein cho n khi loi hon ton protein. .Khi chit xut mu ph tng, cn cht c thu c ln nhiu m, nht l lecithin do ete ko theo cc cht ny. Chemary ngh giai on cui ca qu trnh x l mu nn thay cn bng aceton (v lecithin khng tan trong aceton), sau chng ct loi aceton.Trong trng hp mu ph tng, dung ch cn sau khi loi ht protein s lm dung dch nc c mu nu v lp ete hay cloroform c mu nu en. Kohn Abrest ngh nn c giai on loi m khi dung dch nc acid bng ete du ho trc khi chit bng dung mi hu c.8.4. Phng php tch bng cn-acid, ca SvaicovaX l s b mu th: dng cn 95 pH acid (acid oxalic hay tartric 10%) ngm trong 24 gi. Thu dch cn, loi b cn thu c hn hp sir. Tip tc kt ta albumin bng cn 95 v loi b bng cch lc vi ete du ho.Chit li bng ete hay cloroform.Loi dung mi v lm cc phn ng xc nh.8.5 Phng php tch bng cn - acid ca Kohn AbrestX l s b mu th: tng t phng php ca Svaicova.Chit bng ete mi trng acid.Chit bng ete sau khi kim ho bng NaHCO3 v cui cng vi cloroform ly ht alcaloid.8.6. Phng php chit lin tcNguyn tc l dng mt lng cn nht nh qua h thng hi lu ly ht cc cht cn thit.

9. Cc phng php chung xc nh cht c hu cC th xc nh cht c bng nhiu phng php khc nhau.Phng php dng phn ng ho hc c hiu.Phng php chit o mu. Phng php ph (IR, NMR, khi ph ...). Cc phng php sc k (HPLC, sc k kh ...)10. PHNG PHP PHN TCH CHT C KHc cht kh bao gm cc loi kh c thi trong qu trnh sn xut cc nh my, x nghip nh Cl2, CO, CO2, SO2, H2S, NO, NO2 ... Ly mu khng khiC nhiu dng c ly mu: bm tay, bnh ht bng nc, bnh chn khng, bm lin tc... Phn lp cht c t mu khng kh:Nng ca cht c trong mu khng kh c th c xc nh trc tip trn dng c ly mu, trong mt s trng hp phi chit t mu khng kh bng phng php vt l hay ho hc thch hp.Phng php c chn chit xut hi hoc kh ph thuc vo tnh cht ho hc v l hc ca n. Cc cht kh d tan hoc d phn ng cho sc qua mt cht lng. Nu cc cht kh hoc hi khng tan d dng bng cch trn th c th cho qua cht hp ph rn nh than hot, silicagen, bt cellulose.143

CAC CHT C DANG KHICARBON MONOXID (CO)

1. I CNGCarbon monoxid (CO) l cht kh cc c, mt trong nhng nguyn nhn ch yu gy tn thng v t vong do ng c cht kh trn ton Th gii.1.1. Ngun gc1.1.1. Ngun gc ngoai sinh:CO l cht kh c to thnh do s t chy khng hon ton (khng oxy to thnh CO2) ca carbon hay cc nhin liu c cha carbon (g, than, xng du, kh t ...): nhit cao: O2 + 2C 2COCO c th hin din trong cc nh my, l k ngh (luyn gang thp, ho du, giy...), khi thi t xe c, ng c t trong, l than, l si, ging su, khi thuc l ....Trong t nhin, CO c to thnh t phn ng quang ho ca tng i lu, s hot ng ca ni la, chy rng, chy nh, chy n hm m v cc s chy khc.1.1.2. Ngun gc ni sinh:CO c th c to thnh trong c th t: S chuyn ho ca metylcloride (diclorometan) ti gan. S chuyn ho ca Hem thnh biliverdin di tc ng ca enzym hem oxygenase.Qu trnh ny gia tng trong bnh thiu mu huyt tn.1.2. Tnh cht CO l mt cht kh khng mu, khng mi, khng v, khng gy kch ng nn rt nguy him v kh nhn bit, hi nh hn khng kh, iu kin bnh thng tan rt t trong nc, tan trong etanol v benzen, c th chy vi ngn la mu xanh lam to thnh CO2, CO khng b hp ph bi than hot v c th chui qua lp bc ca cc mt n phng c thng thng. CO c th b oxy ho thnh CO2 bi cc oxid kim loi nh Ag2O, CuO, HgO, MNO2...Phn ng ny c ng dng kh c trong cc mt n phng oc CO. Thi gian bn hu l 5 gi - 6 gi.2. C TNH2.1. C ch gy c2.1.1. Tc ng trn protein HemHemoglogin: CO c th kt hp d dng vi hemoglobin to thnh carboxy hemoglobin (HbCO) rt bn vng, lm mt kh nng vn chuyn oxy trong mu, gim s phn b oxy n m (ng cong phn b oxyhemoglobin b dch chuyn sang tri). i lc kt hp gia CO v hemoglobin mnh gp 250 ln so vi oxygen.Cytocrom oxydase: CO kt hp vi enzym cytocrom oxydase gy c ch h hp t bo.Myoglobin: CO kt hp vi myoglobin lm gim s dng oxy, dn n suy gim s co c tim, h huyt p, v thiu mu cc b no. i lc kt hp gia CO v myoglobin mnh gp 60 ln so vi oxygen.2.1.2. Tc ng trn h thn kinh trung ng:CO gy s peroxid ho cc hp cht lipid (cc acid bo cha bo ho), dn n ph, hoi t v thoi ho t bo no. S tn thng no xy ra ch yu trong thi k hi phc, nh hng n nhn thc, tr nh, kh nng hc tp v gy ri lon vn ng.Do , c tnh ch yu ca CO l do hu qu ca s thiu oxy m v thiu mu cc b.No v tim l c quan tiu th oxy cao v nhy cm vi s thiu mu cc b nn b nh hng nghim trng nht.2.1.3. Tc ng trn bo thaiCO gy thiu oxy m bo thai do gim s cung cp oxy t m n bo thai. Ngoi ra, CO cn qua c nhau thai kt hp vi HbF gy thiu oxy m trc tip.CO c i lc vi HbF cao hn so vi HbA t 10-15% v s o thi CO bo thai li chm hn so vi ngi ln, nn CO c c tnh rt cao i vi thai nhi.2.2. Liu c Nng CO trong khng kh 1.000 ppm (0,1%): gy nhiu triu chng ng c nng dn n t vong. Nng gy nguy him ngay (IDLH: immediately danggeous to life or health) l 1200 ppm.Gii hn nng CO cho php tip xc trong thi gian lm vic 8 gi l 25 ppm (Theo ACGIH)3. HON CNH NHIM C Do s c: cc thit b dng trong gia nh (bp nu bng gas, than, ci, l si, my pht in cc ng c t trong) s dng hay bo tr khng ng, vn hnh ni kn, khng thng kh tt. Do c: t t. Do tai nn: chy n hm m, xung hm su, ging su, ho hon... Do nhim mi trng: khi xe, kh thi nh my... Do ngh nghip: th rn, c kim loi, th co ng khi, th m, cng nhn lm trong cng ty xng du, ti x, cnh st giao thng... phng ng c COKhng nn: Ng trong phng c s dng my si chy bng xng hay du khng c ch thot kh. S dng my mc, gia dng chy bng xng trong nh. un nu trong nh ng ca kn bng l than, ci. Cho n my xe trong garage ng ca kn.Nn: Kim tra thng xuyn cc my mc chy bng xng hay du, l si, m bo ng khi v ng thot kh hot ng tt. C my pht hin kh CO (CO detector).4. TRIU CHNG NG C4.1. Ng c cp4.1.1. Ng c nh Nhc u, th nhanh, bun nn, nn ma, chng mt, hoa mt, au bng, mt mi.Thng nhm ln vi triu chng ca bnh cm, ng c thc n, au d dy...4.1.2. Ng c nngGy ra nhng triu chng ri lon tim mch nh tim p nhanh, h huyt p, lon nhp tim v nhng triu chng h thn kinh trung ng nh m sng, o gic, chng mt, mt phng hng, kch ng, l ln, ngt, hn m, co git, suy nhc thn kinh, sau ngng h hp v cht rt nhanh.Nhng triu chng t gp hn gm c thiu mu c tim, vim phi, ph phi, nhim acid lactic, suy thn cp, ri lon th gic. Nu iu tr kp thi, vn cn cc di chng v thn kinh nh hi chng Parkinson, gim tr nh, ri lon tm thn, t lit thn kinh, au t chi, yu c, i sng thc vt ko di. Nu cht th t thi c sc thi c bit nh mi , c nhng vt o thm i v bng v mu nhimCO c mu o ti.S lin quan gia cc triu chng ng c cp CO v nng HbCO trong mu c trnh by trong bng sau:Bng 1.1. Triu chng ng c cp CO theo nng HbCO trong muNng HbCO (%)Triu chng

5Cha c triu chng

10Nhc u nh, kh th.

20Nhc u m , kh th

30Nhc u nhiu, kch ng, mt mi, hoa mt, mt phng hng

40-50Nhc u d di, tim p nhanh, m sng, o gic, l ln, h huyt p, ngt lm.

60 -70Hn m, co git, try tim mch, try h hp

80Ngng h hp, cht rt nhanh.

>80Cht ngay lp tc

4.2. Ng c mn tnh Nhc u lin tc, bun nn. Suy nhc. Trm cm, l ln, mt tr nh.5. IU TRNhanh chng a nn nhn ra khi ni nhim c.Tng cng h hp: H hp nhn to. Liu php oxy.Oxy 100%, hn hp carbogen (95% oxy + 5% CO2): T1/2 gim cn 1,5 gi.Oxy cao p (100% oxy, p = 2-3 atm): c p dng trong trng hp ng c nng (nng HbCO > 25%), ph n c thai v tr s sinh tng tc thi tr CO. T1/2 gim cn 20 - 30 pht.Liu php oxy c s dng cho n khi nng HbCO gim cn < 5%.Thay mu hoc truyn mu, dng thuc tr tim.iu tr hn m hay co git nu c.Theo di in tm lin tc trong vi gi sau khi ng c.p m v nn nhn yn tnh.6. KIM NGHIM6.1. Xc nh CO trong khng kh CO c hp thu c bit trong vng t ngoi v c th phn bit vi cc kh khc. Da vo phn ng kh I205:I205 + 5CO 5CO2 + I2Chuyn CO2 thnh ta BaCO3 hay chun iod gii phng. nh lng nhanh, ngi ta tm dung dch I2O5 trong H2SO4 c vo bt silicagen v cho vo ng thu tinh. Ht khng kh c CO vo, iod s gii phng lm ng c mu, nh lng bng cch so snh vi gam mu.6.2. Xc nhCO trong mu6.2.1. nh tnh: thc hin trn mu th v mu chng (mu bnh thng) l mu ton phn, c x l chng ng bng heparin, EDTA hay fluorid/oxalat0,1ml mu + 2ml dung dch NH4OH (0,01mol/L), lc mnh s thy mu c CO c mu hng, mu chng mu xm.6.2.2. nh lng: Carbon monoxid c th c phng thch t hemoglobin, sau c nh lng bng phng php sc k kh hay c th nh lng gin tip di dng carboxyhemoglobin bng phng php o quang ph.6.2.2.1. Phng php o quang ph: Da trn c tnh hp thu quang ph c trng ca carboxyhemoglobin.Nguyn tcHemoglobin v cc dn xut ca n c di hp thu c trng vng nh sng kh kin m c th c s dng xc nh nng carboxy hemoglobin.Oxyhemoglobin v carboxyhemoglobin c di kp ging nhau trong dung dch kim. Cc i hp thu ca oxyhemoglobin l 576 - 578nm v 540 - 542nm; ca carboxyhemoglobin l 568 - 572nm v 538 - 540nm. Deoxyhemoglobin c mt di n rng 555nm. Nu mu pha long trong dung dch kim yu c x l vi sodium hydrosulfit, oxy hemoglobin v bt k methemoglobin no hin din s b bin i thnh deoxyhemobin. Carboxyhemoglobin khng b nh hng bi cch x l ny.HbO2 (hay MetHb) + Na2S2O4 HbHbCO + Na2S2O4 khng phn ng hp thu ca dung dch ny c o bc sng 541nm v 555nm.Tnh t s hp thu A541/A555 v nng ca carboxyhemoglobin c xc nh t ng cong chun .Phng php o quang thc hin nhanh chng, thun li, t yu cu v ng v chnh xc, nhng ch p dng i vi mu c nng HbCO > 3%.6.2.2.2. Phng php sc k khNguyn tc: Mu c x l vi kaliferricyanid, carboxyhemoglobin chuyn thnh methemoglobin, co c phng thch vo trong pha kh. Xc nh co phng thch bng phng php sc k kh vi ct ry phn t v detector dn nhit.Phng php sc k kh c ng v chnh xc cao ngay c nng CO thp, nhng li i hi phi c trang thit b chuyn bit.

NITROGEN OXID (NOx)

Nitrogen oxid tiu biu cho mt nhom cht kh c cng thc tng qut l NOx. Nhom ny gm c nitric oxid hay nitrogen monoxid (NO), nitrogen dioxid (NO2), nitrogen trioxid (N203), nitrogen tetroxid (N204), v nitrogen pentoxid (N205).c nht ca nhom ny l nitric oxid v nitrogen dioxid s c kho st trong chng ny.1.NGUN GCNitrogen oxid (nitric oxid v nitrogen dioxid) l nhng cht kh ho hc nguy him thng c phng thch t phn ng gia acid nitric hay acid nitrous vi cc cht hu c, t s t chy nitrocellulose v cc sn phm khc. Nitrogen oxid cng hin din trong khi thi ca xe c. Chng cng c to thnh khi ht d tr vi nng nitrit cao b ln men trong kho d tr.Trong t nhin, nitrogen oxid c to thnh trong qu trnh oxy ho cc hp cht c cha nit nh than, du diesel ... Nitrogen oxid cng c to thnh trong qu trnh hn h quang in, m in, chm khc, chy n, l thnh phn ca nhin liu tn la, phn ng nitrat ho nh trong s sn xut cht n c cha nit, sn xut acid nitric. Nitrogen oxid cn l cht trung gian trong qu trnh sn xut sn mi, thuc nhum, nhng ho cht khc, l thnh phn quan trng ca khi quang ho...2.TNH CHT2.1Nitrogen monoxidNitrogen monoxid l cht kh khng mu nhit thng, khng mi, khng gy kch ng, t tan trong nc.Nitrogen monoxid b oxy ho nhanh trong khng kh to thnh nitrogen dioxid, do s ng c nitrogen oxid ch yu l do nitrogen dioxid.2 NO + O2 2 NO22.2.Nitrogen dioxidNitrogen dioxid l cht c th dng long hay dng kh c mu nu hi o, mi hc c trng, t tan trong nc, c th gy hoi t, thm qua ph nang. Nitrogen dioxi c c tnh mnh hn nitrogen monoxid.Nitrogen oxid l cc kh khng th chy, tuy nhin, chng s thc y s chy ca nhng nhin liu d chy.3.C TNH3.1.C ch gy cNitrogen oxid hu hoi phi qua 3 c ch: Bin i thnh acid nitric v acid nitrous ng kh ngoi bin, ph hu vi loi t bo chc nng v cu trc ca phi. Khi u qu trnh to thnh cc gc t do gy oxy ho protein, peroxid ho lipid lm hu hoi mng t bo. Lm gim khng i vi s nhim trng do thay i chc nng min dch ca i thc bo. Ngoi ra, nitrogen oxid c th oxy ho Hb thnh methemoglobin.Ng c nitrogen oxid c th gy ph phi, vim phi, vim ph qun, kh thng, to methemoglobin. Ho, th nhanh, kh th, nhp tim nhanh, thiu oxy m. Nhng ngi nhy cm c bit vi nitrogen oxid gm c ngi b hen suyn, bnh phi tc nghn mn tnh, bnh tim.Hu ht cc nitrogen oxid nng cao l nhng cht kch ng da, mt, v ng h hp. Nhng triu chng ban u v h hp c th nh, nhng s vim phi tin trin c th xy ra sau vi gi n vi ngy.Nitrogen dioxid l cht gy hoi t, c c tnh mnh hn nitrogen monoxid.Nitrogen monoxid l cht gy methemoglobin nhanh v mnh.Con ng ch yu ca s ng c nitrogen oxid l ng h hp. Nhng d cho tip xc bng bt k ng no cng c th gy tc ng trn ton thn.3.2.Liu cTheo (American Conference of Government Industrial Hygienists) ACGIH:Nng tip xc gii hn tn ni lm vic: Nitric oxid (NO): 25 ppm (31mg/m3), Nitrogen dioxid (NO2 ): 3 ppm (5,6mg/m3).Nng nguy him ngay: Nitric oxid (NO): 100 ppm Nitrogen dioxid (NO2 ): 20 ppm.4.TRIU CHNG NG C 4.1.Ng c cpC th c nhng triu chng tc thi khi ng c nitrogen oxid nh ho, mt mi, bun nn, khn ting, nhc u, au bng, kh th. Thi k khng triu chng khong 3 - 30 gi trc khi chuyn sang bin chng ph phi vi cc triu chng nh bn chn, ri lon tm thn, hn m, bt tnh.H h hp nng thp, NO2 ch gy kch ng nh ng h hp trn do kh tan trong nc, c th gy th hi nhanh, ho. Sau vi gi n vi ngy, c th tin trin sang vim phi vi cc triu chng ho d di, nhp th nhanh, gim oxy huyt hay co tht ph qun v ph phi. S tin trin ny c th xy ra nhanh hn khi ng c liu cao. nng cao s gy kch ng mnh ng h hp, trc tin l ng h hp di gy bng, co tht, ph m c hng. Nn nhn thy kh chu, yu, st, n lnh, th gp, ho km theo au ngc, chy mu phi hay ph qun, da xanh v try h hp, c th tc nghn ng h hp trn. S tc nghn ph qun c th ko di nhiu ngy sau khi b ng c nng v gy t vong.H tim mchMch yu v nhanh, ngc sung huyt, try tim mch.H tiu hoKhi ung phi nitrogen oxid dng lng s gy kch ng hay t chy ng tiu ho.MuNg c liu cao c th bin i Fe2+ thnh Fe3+ vi tc ng ca nitrogen monoxid gy methemoglobin v lm gim kh nng vn chuyn oxy.DaNitrogen oxid nng cao gy kch ng da v hoi t. Da m t tip xc vi nitrogen dioxid dng lng hay dng hi nng cao c th to thnh acid nitric gy bng da. Acid nitric cng c th lm da c mu vng hay hu hoi men rng.Th gicTip xc vi nng tng i cao c th gy kch ng mt v vim.Nitrogen dioxid dng lng c th gy bng mt sau khi tip xc. Dng kh vi nng cao gy kch ng v sau khi tip xc lu di c th b m mt hay m mt.4.2.Ng c mn tnhNg c mn tnh nitrogen oxid gy nguy c nhim trng h hp tr em. Bnh phi tc nghn mn tnh c th xy ra do ph qun b hu hoi.5. IU TR Khng c antidot cho ng c nitrogen oxid. iu tr ch yu l tr h hp v tr tim mch. Cung cp oxy v dng thuc gip cho s h hp d dng hn. Xanh methylen c th s dng iu tr methemoglobin khi nn nhn c du hiu thiu oxy m hay c nng methemoglobin > 30%, cht ny khng c tc dng i vi bnh nhn b thiu enzym G6PD v c th gy huyt tn. Liu dng l 1 - 2mg/kg th trng (0,1 - 0,2ml dung dch 1 %o/kg th trng) tim tnh mch. Liu khi u khng > 7mg/kg. Ra vng da b nhim hay mt ngay vi nc hay nc mui lin tc trong t nht 20 pht. Nu nn nhn ung phi dung dch nitrogen oxid, khng gy nn, khng cho ung than hot v c th lm m n ni soi ( kim tra ng tiu ho b kch ng hay bng), cho ung nhiu nc hay sa. Theo di cht ch cc du hiu ca s tc nghn ng h hp trn, c th lun ng vo kh qun v h tr thng kh nu cn. Cung cp oxy b sung. Theo di nhng nn nhn c triu chng trong t nht 24 gi. iu tr vim phi v ph phi nu c (c th dng corticosteroid).7.CHN ON Thng da vo lch s ng c, nu bit r. NO v NO2 c chuyn ho thnh nitrit (NO2-) v nitrat (NO3-) v bi xut ra nc tiu. Do , o nng ca cc cht chuyn ho ny trong nc tiu c th gip xc nh s ng c. Ngoi ra, c th o oxy hay kh ng mch, nng methemoglobin, chp X quang v kim tra chc nng ca phi.

MT S CHT C V C IN HNH

Mc tiu hc tp1. Gii thch c nguyn nhn gy ng c cp tnh v trng din ca cc kim loi: bari, ch, arsenic, thy ngn, ng, km, crom v sulfamit2. Thc hin c cc phn ng nh tnh ca by kim loi v sulfamit nu trn.3. Trnh by c tnh, nguyn nhn gy ng c, x tr ng c cc kim loi v cc bin php phng nhim c

1. Cc cht c phn lp bng phng php v c ha1.1. Barium1.1.1. Dn xut v nguyn nhn ng c. Bari l kim loi c thuc nhm kim th, a s cc mui ca n u c, nht l nguyn t bari phng x: 140Ba. Cc mui ca Bari gm c:- Bariclorua (BaCl2.2H2O), cht kt tinh trng, v rt kh chi, tan tt trong nc v khng tan trong cn.- Bari cacbonat (BaCO3), khng tan trong nc, nhng tan trong axit k c trong nc c CO2. Bari cacbonat c dng git chut, dng trong pha ch sn.- Bari sulfat (BaSO4), thc t khng tan trong nc v cc axit nn khng c. Trong y hc bari sulfat c dng lm cht cn quang.- Bari fluoro silicat (BaSiF4), t tan trong nc, thng dng git su b.Ng c do mui bari thng xy ra do ung nhm thuc nh: nhm natri sulfat, kali bromur vi bari clorua, nhm bari sulfat vi bari cacbonat.Ng c cng c th xy ra do ung thuc cn quang bari sulfat c ln nhiu tp cht bari d tan.1.1.2. Phng php kim nghim. Bari sau khi phn lp t mu th, chuyn thnh dng mui ha tan ri tin hnh nh tnh v nh lng.* nh tnh:- Phn ng kt tinh li BaSO4 t axit sulfuric m c: kt ta BaSO4, ly mt t kt ta trn vi 1-2 git axit sulfuric c trn phin knh v un nng. Sau khi ngui s thy nhng tinh th bari sulfat hnh ch thp v hnh vung. nhy ca phn ng 0,05g trong mu th.- Phn ng vi dung dch kali cromat: to ta bari cromat mu vng, khng tan trong axit acetic v kim. C th dng phn ng ny phn bit bari vi ch- Phn ng vi dung dch natri rodizonat mi trng trung tnh: cho kt ta mu nu , khng mt i khi thm HCl 10%.- t trn ngn la khng mu; cc mui bari cho mu lc.* nh lng: c nhiu phng php nh lng bari:- Phng php trc quang: cho Ba2+ phn ng vi kali cromat pH = 5,5; thm 2 th tch hn hp cn v aceton (3:2). Kt ta c ngm trong dung dch focmol long (1:2). un cch thy si t pht. Sau ngui, trung ha v kim ha long bng amoniac chuyn focmol thnh urotropin. ngui, ha tan bari cromat trong dung dch HCl long ri so mu trc tip hay lm phn ng to phc mu ca cromat vi thuc th diphenylcacbazid mi trng axit. Phc c mu hng tm.- Phng php th tch: cho complexon d vo dung dch c bari. xc nh phn d bng dung dch chun km clorua vi ch th en eriocrom T (chun ngc).1.1.3. c tnh. Tr bari sulfat, cc mui khc ca bari u c. Liu c i vi bari clorua l 2-4g, vi bari cacbonat 10-20g.Khi ng c mui bari ha tan thng nn, a chy. Cn ra d dy bng dung dch natri sulfat 1% hay magnesium sulfat. Ung dung dch natri sulfat 10%. Tim cc thuc tr tim.1.2. Ch1.2.1. Dn xut ca ch. Ch l mt kim loi mm, mu xm. ch to c nhiu hp cht khc nhau c ng dng trong thc t nh:Ch oxid PbO, ch hydrat Pb(OH)2: bt mu trng t tan trong nc, tan trong kim NaOH hay KOH tha.- Minium Pb3O4: bt mu khng tan trong nc, minium c th coi nh l s kt hp ca ch oxid v ch dioxid: 2PbO.PbO2. Minium c dng pha sn, dng trong k ngh thy tinh, lm cht mu cho gm...- Ch cacbonat PbCO3: dng pha mu sn.- Ch cromat PbCrO4: mu vng dp, dng pha sn mu.- Ch sulfit PbS: dng to lp trn mt gm- Ch acetat Pb(CH3COO)2.3H2O: dng nhiu trong phng th nghim, trong y hc.1.2.2. Nguyn nhn gy ng c. Ch v hp cht ca n t gy ng c cp tnh v chng c mi v rt kh chi nn kh ung. Nhng i khi chng c th gy tai bin nh:- ng natri clorua ng trng vo chai thy tinh c pha ch,- Ng c c th xy ra do tr em ngm chi c pha chTrong thc t thng xy ra ng c trng din do tch ly ch trong thi gian di. Cc nguyn nhn gy ng c trng din c th l:- n cc thc phm ng hp hn bng thic-ch- Ung nc dn qua ng ng pha ch- Ht phi bi ch v cc hp cht ca n trong cc nh my sn xut sn, lm accu, m kim loi, khai thc ch v c ch ch.- Cng nhn tip xc vi xng pha ch Pb(C2H5)4.Nguy him nht l ng c ch trng din. Ngi ta tnh cn bng lng ch cho mt ngi th:- nhim khng kh: dng xng pha ch, lng ng ht c ch...a vo ngi khong 10 mcg/ngy.- Nc ung: 15 mcg/ngy.- Thc phm: 200-300mcg/ngy.Trong khi lng ch trong c th trao i 25 mcg/ngy. Nh vy lng d trn 200mcg/ngy, gy nguy him cho hot ng sng ca ngi. Nu lng d khong 1mg/ngy c th gy ng c trng din.1.2.3. S phn b, tch lu v o thi ch.* Phn b v tch lu ch: Xng l t chc lng ng ch nhiu nht t 91-95% di dng phosphat khng tan. Barry v Mosson chng minh rng nng ch trong xng ln hn m mm v xng di ln hn xng dt. Trong cc m mm, ch c nhiu trong no, thn v tu xng, iu ny gii thch cc biu hin lm sng ca nhim c ch.Khi xm nhp vo c th, ch kt hp vi albumin ca mu to thnh dng albuminat ch. trong mu ch c bit gn vi hng cu (90% ch trong mu), phn cn li hoc gn vi protein ca huyt tng, hoc khuych tn, sau n tp trung cc h thng c quan. xng ch di dng hp cht khng tan triphosphat ch Pb3(PO4)2, dng ny khng c. T kho d tr ca xng trong nhng tnh trng nht nh ca c th, ch c chuyn vo li vo mu di dng d phn ly, c ho tan gp trm ln so vi phosphat ch. dng ny ch s gy c cho c th. Mt trong nhng yu t nh hng n s lng ng ca ch l canxi. Cng vi s tng tch lu canxi xng l s tng gi ch trong xng v ngc li.* o thi ch: ch c o thi ch yu qua ng tit niu v tiu ho. ngoi ra ch cn c o thi qua nc bt, qua da v c trong tc, mng, sa v kinh nguyt. Lng ch o thi qua nc tiu c bit quan trng nhng n ph thuc vo tnh trng chc nng thn.1.2.4. Phng php kim nghim1.2.4.1. X l mu th* Kim nghim ch trong khng kh: ht khng kh c bi ch vo axit nitric ri dng phn ng ca ch nh tnh v nh lng.* Xc nh ch trong ph tng v nc tiu: ta PbSO4 to thnh sau khi v c ha bng hn hp sulfonitric c ha tan trong amoni acetat nng ri tin hnh nh tnh v nh lng.1.2.4.2. nh tnh Pb2+* Phn ng vi dithizon to dithizonat ch, chit xut bng cacbon tetraclorua pH = 7-10, nu c Pb2+ lp dung mi hu c c mu ta.Pb(COOCH3)2 + 2H2Dz Pb(Dz)2 + 2CH3COOHPhn mg c nhy cao (0,05 mcg Pb/ml) v trong iu kin phn tch c cht m t, n c tnh c hiu tuyt i. V rng ch dithizonat thu c t Pb2+ trong PbSO4 tc l tch bit c Pb2+ ra khi a s cc nguyn t khc. Trong kt ta PbSO4 c th c Fe3+ Cr3+ i vo dung dhch cng vi Pb2+ sau khi ho tan PbSO4 trong amoni acetat. Nhng v Fe3+ c i lc yu i vi dithizon, cn Cr3+ to vi dithizon hp cht khng mu cho nn chng khng gy cn tr.* Phn ng vi dung dch kai iodua:Pb2+ + 2KI PbI2 + 2K+ ta mu vng Thm nc, un nng PbI2 ho tan to thnh dung dch mu vng, ngui kt tinh tr li cho nhng tinh th vng ng nh. Ngi ta gi l nhng phn ng "ma vng". * Phn ng to kali ch ng hexanitrit: K2CuPb(NO2)6. Cho vi git dung dch Pb2+ ln phin knh bc hi ti kh, thm vo cn 1-2 git dung dch ng acetat bo ho ri li bc hi ti kh. Ho tan cn trong 2-3 git dung dch axit acetic 30% v thm vi tinh th kali nitrit. Nu c Pb2+ s thy cc tinh th K2CuPb(NO2)6 hnh lp phng mu en.* Phn ng to ch sulfit PbS:Pb(NO3)2 + H2S PbS + 2HNO3Kt ta khng tan trong HCl v H2SO4 long nhng tan trong HNO3 long gii phng oxid nit v lu hunh nguyn t:3PbS + 8HNO3 3Pb(NO3)2 + 2NO + 3S + 4H2O* To kt ta PbCrO4 mu vng khng tan trong axit acetic, tan trong axit v c v trong kim n da:2Pb(CH3COO)2 + 2K2Cr2O7 + H2O 2CH3COOK + 2PbCrO4 + 2CH3COOH1.2.4.3. nh lng. Sau khi v c ho mu th, ch tn ti dng PbSO4, n c ho tan .trong amonacetat chuyn thnh Pb2+. C th nh lng Pb2+ bng nhiu phng php:* Phng php dicromat-io: cho dung ch Pb2+ tc dng vi mt.lng tha dung dch kali dicromat chun. nh lng kali dicromat d bng phng php o iod.2Pb(CH3COOH)2 + 2K2Cr27 + HOH 2PbCrO4 + 2CH3COOK + 2CH3COOHK2Cr2O7 + 6KI + 7H2SO4 3I2 + Cr2(SO4)3 + 4K2SO4 + 7H2OI2 + 2Na2S2O3 2NaI + Na2S4O6Phng php ny cho kt.qu tt khi hm lng ch tng i ln (2-10mg ch trong 100g mu th). * Phng php chit o quang vi dithizon: to dithizonat ch pH = 7-10. Chit dithizonat thu c bng cloroform pH > 7,O. Ra dch chit bng dung dch KCN c thm NH4OH. o mt quang ca dch chit cloroform bc sng 520 nm (dung dch so snh l cloroform). Tnh hm lng ch theo th chun. nhy ca phng php l 10mcg/g.* Phng php complexon: nh lng Pb2+ bng cch cho d complexon.(III) 0,01N trong dung dch m amoniac. Chun complexon tha bng dung dch km clorua vi ch th en eriocrom T.* Phng php cc ph: kh ion ch trn catod git thu ngn vi nn amoniaxetat 3%. Th bn sng ca.ch 0,55V. nhy ca phng php 5mcg/ml. Hin nay 3 phng php c khuyn co nh lng ch l:+ Quang ph hp th nguyn t (AAS), Quang ph pht x nguyn t (AES-ICP), Cc ph ha tan anod (ASV).1.2.4.4. c tnhCc mui ch u rt c, c tnh ca n rt phc tp: Ch tc dng ln cc h thng men c bn, nht l men trong qu trnh vn chuyn tng hp heme. y c mt pha quan trng l chuyn ho acid aminolevulinic (-ALA) thnh prophorbilinogen nh men -ALA dehydrase. Pb2+ c ch men ny lm tch lu -ALA trong th, ng thi thiu heme tng hp hemoglobin. Nu Pb2+ trong mu trn 0,3 ppm s ngn cn qu trnh oxy ho glucose to ra nng lng duy tr s sng. Nu hm lng ch/mu trn 0,8 ppm gy thiu mu do thi ht hemoglobin.* Triu chng ng c: Khi ung phi ch s xut hin mt s du hiu: rt mm, nn ra cht trng (PbCL2), au bng, a phn en, to bn. V niu do thn b tn thng, tng ur huyt....Trng hp ng c trng din: xut hin vnh en li rt sm.Ngoi ra ngi ta cn nhn thy:- Tr em nhy cm i vi ch hn ngi ln. C mi tng quan gia mc phi nhim ch v ri lon chc nng ca h thn kinh tr em.- cng nhn tip xc lu di vi ch, ngi ta ghi nhn nhng bt thng ca chc nng hot ng thn kinh v tm thn.- C triu chng v bnh l thn kinh ngoi bin, khi phi nhim lu di vi nng ch cao ni lm vic. Nu nng ch thp hn, tc dn truyn ca h thn kinh ngoi bin gim st.Ch lm.tng s protopocphyrin III t do ca hng cu v copropocphyrin.III ca nc tiu. Vic xc nh s tch lu pocphyrin c tm quan trng ln trong chn on ng c trng din v rng bnh thng mu c rt t protopocphyrin III t do, cn trong nc tiu.khng c copropocphyrin III. chn on ng c trng din ngi ta cn.ng dng th nghim -ALA v copropocphyrin III trong nc tiu* iu tr. Trong ng c cp: ra d dy bng dung dch natri hoc magie sulfat. Cho ung thuc chng c kim loi nng. C th tim truyn tnh mch dung dch natri clrrua ng trng c cha Ca(EDTA). trnh nhim c ch cn phi ch ci thin iu kin iu kin lm vic, gim thiu lng bi ch v cc hp cht ca n xm nhp vo c th. Kim tra sc kho nh k cho cng nhn tip xc vi ch 6 thng 1 ln. nh lng ch trong mu v nc tiu. Xt nghim ur huyt, tm hng cu c chm trong mu. phng nhim ch, tiu chun Vit nam 1995 (TCVN-95) qui nh gii hn 0,05 mg ch/L cho nc ngm v 0,1 mg ch/L cho nc thi cng nghip.1.2.4.5. Nhn nh kt qu- Trong ng c cp tnh thng tm thy lng ch ln ng tiu ho.- nh gi kt qu nh lng ch trong mu v nc tiu chn on ng c trng din, cn ch n lng ch c t nhin trong c th: mc trung bnh ca ch trong mu 0,06 mg/100ml. trong nc tiu 24 gi: 0,08 mg1.3. Arsenic1.3.1. Dn xut v nguyn nhn ng c- Arsenic kim loi l cht c mu xm, ngoi khng kh b oxi ha thnh As2O3.. t chy c mi ti.- Arsenic trioxid As2O3 l mt hp cht quan trng nht ca arsenic, thng gi l thch tn, rt c.- Arsenit: mui ca K, Na axit arsen. Ngoi ra cn c mui ng arsenit; ng aceto arsenit. Hai loi mui ny u c mu xanh lc, dng trong cng ngh nhum giy...- Arsenat: cc mui ca axit arsenic: natri arsenic dng lm thuc sng, ng arsenat c mu xanh lc dng lm phm mu, ch v canxi arsenat dng lm thuc tr su.- Arsenic sulfit: dng trong cng ngh sn.Ng c cp arsenic c th xy ra do ung nhm thuc tr su, do u c hoc t t. Nguyn nhn gy ng c mn tnh bi arsenic c th l:- Dng cc thuc c tp cht arsenic trong thi gian di, arsenic o thi chm, tch lytrong c th.- S dng rau qu c cha d lng thuc tr su cha mui arsenic vt qu gii hn- Do cng nhn khai thc khong vt cha arsenic v sn xut cc hp cht ca arsenic...Mi y (1995), Bngadet, ngi ta pht hin thy trong nc ging ngm ca mt vng c hn mt triu dn b nhim arsenic. Lng arsenic ton phn {As(III), As(V) v arsenic hu c} dao ng t 0,05-3,7mg/L. Hin c khong 200.000 ngi b tn thng da: mt sc t, sng ha. Thc ra, cc trng hp nhim c arsenic u tin c pht hin t nm 1980 do dng nc ging khoan su 20m n 150m. Hin nay khng ch nc ging vng ny m tt c ging khoan cng cha arsenic kt hp vi pyrit. Nguyn nhn nc ging ngm nhim arsenic c th l:- Do vi sinh vt chuyn ho arsenic t khong khng tan nh arsenico pyrit (FeAsS), enargit (Cu3AsS4), orpiment (As2S3)... thnh arsenic ho tan thm vo cc lp nc ngm su trong t.- Cng ngh luyn kim (ng, ch, km, vng), nng nghip, a mt lng arsenic ng k vo mi trng.1.3.2. Phng php kim nghim. V c ha mu th bng hn hp sulfocromic. Dng dch v c ha tin hnh xc nh arsenic1.3.2.1. nh tnh* Phng php Marsh- Nguyn tc: kh arsenic ln ha tr cao bng hydro mi sinh (H2SO4 long v km kim loi) thnh H3As bay ln.H2SO4 + Zn 2H + ZnSO4H3AsO4 + 8H H3As + 4H2OPht hin kh H3As bng cch cho kh i qua mt bnh thy tinh v t ln ti nhit 6000C, kh H3As s phn hy thnh arsenic kim loi v H2. Arsenic s ng li trn thnh ng thy tinh thnh mt vng en nh kim loi. Ly ng c vng xm en ra, t nh s thy cc ht trng bm trn thnh, soi knh hin vi s thy hnh c bit ca As2O3. Phng php ny rt c hiu, nhy cao c th tm c 1mcg As trong dung dch. y l phng php duy nht c gi tr php l. Nhc im ca phng php ny l tn nhiu th gi.* Phng php Cribier- Nguyn tc: phng php ny cng da trn c s ca phn ng kh arsenic ln ha tr cao bng hydro mi sinh thnh kh H3As. Kh ny tc dng vi giy tm HgCl2 hoc HgBr2 cho hp cht mu vng cam hay nu do to thnh cc hp cht arseno thy ngn.H3As + HgCl2 = HCl + AsH2(HgCl)AsH2(HgCl) + HgCl2 = HCl + AsH(HgCl)2AsH(HgCl)2 + HgCl2 = HCl + As(HgCl)3H3As + As(HgCl)3 = 3HCl + As2Hg3- Tin hnh: dng c th arsenic theo phng php Cribier gm mt bnh nn dung tch 100ml y nt cao su gia c mt ng thy tinh di 20 cm xuyn qua, ng knh ng 5 mm, pha di bt kn, cch u ng khong 2,5 cm c mt l thng hi bn cnh, rng 3 mm.Cho vo pha di ng thy tinh mnh giy lc hoc bng tm dung dch ch acetat, sy kh gi kh H2S nu c. Lng vo ng mt di giy tm dung dch HgCl2 5% sy kh, y giy ny cch ming bng ch acetat khong 2 cm. Dung dch tm arsenic phi khng c cn cht oxi ha. Ly 8-10 g km ht, ra sch bng dung dch ng sulfat 5%, ra sch bng nc ct v cho vo bnh Cribier, cha sn dung dch th v iu chnh cho nng axit sulfuric khong 20%. t bnh vo nc lnh v ch ti trong 6 gi. Song song lm mt mu trng.u nhc im: phn ng ny c nhy cao (0,1 mcg trong th tch dung dch em th), tn t thi gian. Tuy nhin phn ng ny khng c hiu v H2S v H3P cng cho mu vng vi giy tm dung dch HgCl2. Cho nn trong kim nghim c cht phng php ny ch c gi tr gii hn. Thng dng phng php ny th s b trc khi thc hin phng php Marsh. Nu phn ng ny m tnh th khng cn lm phn ng Marsh na.* nh lng. C nhiu phng php nh lng arsenic: Vi lng vt, thng s dng cc phng php: AAS, ASV, AES-ICP NAA...Sau y l s phng php xc nh a lng arsenic:+ Phn ng Marsh: t cc lng arsenic khc nhau trong ng Marsh xong hn li v dng lm chun so snh vi ng th.+ Phn ng Cribier: lm gam mu th trong cng iu kin vi mu th. Nhng cc gii tm HgCl2 to nu vi arsenic vo dung dch KI 10% c nh mu. Sau so snh vi di ca giy c mu mu th vi gam mu.+ Phng php DDTC-Ag: dng km trong mi trng axit kh arsenic thnh H3As. Kh ny c dn qua bnh c cha thuc th DDTC-Ag ha tan trong pyridin. Phn ng to phc mu c max 535 nm. Phng php ny rt nhy c th pht hin c 0,002ppm arsenic

SH -O [Enzym] + As - O SH -O S [Enzym] As - O- + 2OH- S

1.3.2.2. c tnh. Cc hp cht ca arsenic tc dng ln nhm thiol-SH ca cc enzym lm cn trhot ng ca enzym. Ngoi ra arsenic cn lm ng t protein,v ph hy qu trnh phospho ha.Liu c rt kh xc nh v thng phn ln cht c b nn ra ngoi. Ngi ta cho rng liu ung thc s As2O3 l 0,002g/kg c th cht trong 24 gi. Liu c dn xut arsenic hu c thng cao hn. Bi vy c th ung ti 0,6g natri cacodylat mt ngy tc l mt lng arsenic 40 ln cao hn th As2O3 m vn cha gy ng c.Liu c ca arsenic cn thay i ty theo tng ngi, nht l nhng ngi dng cc thuc c cha arsenic. V d vua Mithridate thi La m c i v s ngi ta u c mnh nn hng ngy ung mt lng nh arsenic quen thuc.Cc mui arsenic tan nhanh trong nc, hp thu nhanh qua nim mc tiu ha v tch ly cc t chc: gan, lch, thn, nim mc rut, phi, lng, tc, mng. Thi tr chm qua rut v thn.Triu chng ng c: ng c arsenic chia lm ba th:+ Th ti cp (sau na gi vi 0,5-1g As2O3): du hiu in hnh ca th ny l nn ma, au bng d di, a chy v a ra mu, phn ln nhn ht trng...+ Th cp (sau na gi vi 0,10-0,20g As2O3): biu hin cc triu chng nh au vng thng v, a chy d di, ri lon thc...+ Th mn tnh: biu hin cc du hiu sau: ri lon tiu ha, gy st nhanh. Gy tn thng trn da, thiu mu , gim bch cu ht...1.3.2.3. iu tr+ i vi th cp:- Loi tr cht c ra khi c th cng nhanh cng tt bng cch gy nn v ra d dy vi lng trng trng.- Trung ha cht c bng cc cht chng c nh cc dung dch c sulfit, mui Fe3+, magnesium oxid...Tim thuc iu tr c hiu B. A. L (British antilewiste: CH2SH-CH.SH-CH2OH) vi liu 3mg/kg.- Truyn huyt thanh mn, ngt. Dng thuc tr tim, li tiu, methionin.+ i vi th mn: Ch yu iu tr bng phng php vt l.1.3.2.4. Nhn nh kt qu kim nghim. Khi nh gi kt qu kim nghim arsenic, cn ch ti cc thnh phn t nhin ca arsenic trong mu th nh:- Lng arsenic trong ton b ph tng ngi ln khong 0,3 mg.- Arrsenic c trong mt s loi c, trong hoa qu phun thuc tr su c arsenic.- Arsenic trong dc phm, trong mi trng (nc t nhin, t).Nu tm thy vi centigam trong ton b ph tng th c th xem nh ng c arsenic. Nu tm thy vi miligam th cn xem bnh nhn c ung thuc cha arsenic hay khng. Hin nay phng nhim c arsenic, FAO-OMS chp nhn:- Lng arsenic a vo c th hng ngy l 0,002mg/kg,- Arsenic trong nc b mt 0,01 mg/L.TCVN-95 qui nh gii hn 0,05 mg/L cho nc ngm v 0,01 mg/L cho nc thi cng nghip.1.3.2.4. V d minh ha. nh lng arsenic trong nc bng phng php DDTC-Ag.* Ly 20-30 mu nc, thm 5 ml HCl c, 2 ml dung dch KI 15% v 0,5 ml thuc th SnCl2 40%. Lc u, yn 15 pht, chuyn dung dch sang bnh phn ng to H3As.* Thm 3g km ht vo bnh y ng bng ng c tm ch acetat 10%. Dn kh qua bnh c cha 4 ml DDTC-Ag trong pyridin. yn 45 pht.* o hp th quang = 535 nm so vi mu trng. Tnh nng theo phng php ng chun trong khong 0,002-0,1 ppm arsenic.1.4. Thy ngn1.4.1. Dn xut+ Thy ngn kim loi: l kim loi lng nhit thng, bc hi. Nng hi thy ngn bo ha nhit 200C l 20 mg/m3 nn c th gy ng c qua ng h hp.+ Thy ngn(I)clorua-Hg2Cl2: bt trng khng mi, khng v, khng tan trong nc v dung mi hu c. Cc yu t nh: nhit , axit clohydric, mui natri hydrocacbonat chuyn n thnh HgCl2 lm tng c tnh.+ Thy ngn(II)clorua: tan trong nc, dng lm cht dit khun.+ Thy ngn(I)nitrat Hg2(NO3)2.2H2O+ Thy ngn(II)nitrat Hg(NO3)2.8H2O thng c dng trong dung dch HNO3 t chy ch vim.+ Thy ngn(II)cyanur Hg(CN)2.+ Cc hp cht thy ngn hu c: ethyl thy ngn clorua (Cl-Hg-C2H5), ethyl thy ngn phosphat, methyl thy ngn nitrit...lm thuc tr su, tr nm.1.4.2. Ngun gc nhim c+ Ngun gc t nhin: do qu trnh thot kh ca v tri t, s phun tro ni la (2700-6000 tn/nm).+ Ngun gc nhn to: t nhin liu ho thch, luyn qung kim loi sulfit, tinh luyn vng, sn xut xi mng, thiu t cht thi rn....Mt s ngi dn da mu chu phi dng kem v x phng c thy ngn lm sng da. X phng cha 3% thy ngn iodua,. Nhng sn phm ny t lu b cm lu hnh chu u v Bc M, nhng ti mt s nc chu u vn cn sn xut x phng c thy ngn. Hng nm c khong 3000 tn thy ngn c thi vo kh qun do hot ng ca con ngi.1.4.3. Phng php kim nghimKhi v c ha mu th, di tc dng ca nhit, thy ngn b bay mt mt phn nn cn phi chn phng php thch hp khng b mt thy ngn khi v c ha mu. Nu dng phng php sulfonitric th dng li giai on cht hu c tan r thnh cht lng mu sm. Nu ch mun tm thy thy ngn th nn dng phng php v c ha bng kh clo mi sinh.1.4.3.1. nh tnh* To hn hng vi ng kim loi (nghim php Reinsch). Phn ng ny c th thc hin trc tip trn mu th v c ha. Ly mt t mu th cho vo bnh nn, axit ha bng HCl n.khi pH < 6, cho bnh mt mnh ng kim loi co sch v ra bng HNO3 long v nc ct. un nng trong khong mt gi. Nu c Hg2+ th trn b mt mnh ng s c mt lp kim loi sng bng (thy ngn kim loi). Sau ra mnh ng bng nc ct v ether ri kh ngoi khng kh, cho vo mt ng nghim kh cng vi vi tinh th iod. Cun mt di giy lc tm t vo v tr 1/3 ng k t y ri t nng nh. Nu c Hg2+ th s c nhng tinh th thy ngn iodua bm phn ng lm lnh. t ng ln knh hin vi s thy tinh th hnh thoi mu tm hng.* Phn ng vi Cu2I2: cho mt t ta Cu2I2 ln mt mnh giy lc ri t vo mt mnh ng to hn hng sng bng, y li bng mt knh ng h. Vi pht sau thy mu hng trn nn trng.* Phn ng vi dithizon: cc mui thu ngn (II) to vi dithizon mt phc cht mu vng cam bn vng pH 0,5-1,0.* Phn ng vi dung dch kali iodua: Cc mui thu ngn(II) cho kt ta mu HgI2 vi dung dch KI mi trng trung tnh hay axit nh v tan trong thuc th tha.* Phn ng vi thic (II) clorua: cho kt ta trng (pH 2,5) ri chuyn sang xm.1.4.3.1. nh lng. C nhiu phng php nh lng thu ngn nh: AAS, ASV, AES-ICP NAA...* Phng php so mu vi ng (I) iodua Cu2I2. Phng php ny da trn c s ca phn ng Hg2+ vi dung dch KI to thu ngn iodua. Sau thu ngn iodua kt hp vi ng (I) iodua to thnh phc mu hng Cu2(HgI4). So mu vi thang chun.Hg2+ + 2KI = HgI2 + 2K+HgI2 + 2KI = K2HgI42CuSO4 + 4KI = 2CuI2 + 2K2SO4K2HgI4 + 2CuI = Cu2(HgI4) + 2KII2 + Na2SO3 + H2O = 2HI + Na2SO4* Phng php chit o quang vi thuc th dithizon: to dithizonat thu ngn. o quang vi dy chun bc sng 496 nm.1.4.3.2. c tnh. Thu ngn kim loi ch c th hi. N tc dng qua ng h hp chuyn thnh albumat ho tan v vo mu. Thu ngn di dng Hg2+ rt c. N tc dng ln nhm thiol (-SH) ca cc h thng enzym c bn. Liu c ca thu ngn (II) clorua vi ngi ln l 0,20-0,30g. Vi liu 0,40-1mg hng ngy v lin tc trong thi gian di c th gy ng c mn tnh. cc hp cht thu ngn hu c t c hn, chng gy ri lon tiu ho, chc nng thn v thn kinh.* Triu chng: khi ng c thu ngn (II) clorua nim mc ng tiu ho b bng, lot. Nn ra cht nhy v mu, a chy, phn c mu. Thn nhit h, v niu, vim li. Khi ng c mn tnh thng thy cc ri lon tiu ho, vim li, ri lon tm thn, run chn tay.* iu tr ng c cp:- Ra d dy bng nc lng trng trng hay nc c thm cht chng c thu ngn nh rongalit.- Cho ung thuc chng c c sulfit, ung nc lng trng trng, sa, sau li ra d dy trnh cc hp cht tan li.- Truyn tnh mch rongalit 10g trong 100-200 ml nc ct sau 4-6 gi, tim nhc li trong cc trng hp nng.- Tim bp B.A.L 5 mg/kg c th.1.4.3.3. Phn b, chuyn ho, bi tit thu ngn trong c th sng. Sau khi vo c th thu ngn c vn chuyn n mu. y n c gn vi gc thiol (-SH) ca protein huyt tng. Trong mu cng nh trong t chc, Hg kim loi v hp cht mercuro c oxi ho, mui mercuric hnh thnh nhng hp cht tan vi protein, vi kim mu v dch lng ca t chc. Tc dng c ca thu ngn c gii thch do s ho tan trong m cng nh vic oxi ho ion mercuro thnh ion mercuric. Thu ngn kim loi c oxi ho thnh ion ho tr II qua c ch enzym. Phn ng ny xy ra hng cu nhng n cng c xy ra cc t chc, m khc. Phn thu ngn cn li trong mu c vn chuyn ti hng ro mu no v rau thai. Do tnh tan trong m cng nh kh nng khuych tn ln, thu ngn c th d dng qua hng ro ny. Vic oxi ho thu ngn y dn n s tch lu thu ngn m no v phi thai. - S phn b m v gi li trong c th: hi thu ngn c tch lu no vi mt lng ln. Vic o thi thu ngn ra khi no xy ra chm, iu ny ph hp vi nhn xt l h thng thn kinh