Li ni u: TCVN 5455: 1998 hon ton tng ng vi ISO 2271: 1989 TCVN 5455: 1998 thay th cho TCVN 5455- 72 TCVN 5455:1998 do Ban k thut tiu chun TCVN / TC 47 Ho ch t c b nbin

son,Tng cc Tiu chun o lng- Cht lng ngh, B Khoa hc, Cng ngh v Mi trng ban hnh.

TIU CHUN VIT NAM TCVN 5455-1998

Sot xt ln 2 CHT HOT NG B MT - CHT TY RA

XC NH CHT HOT NG ANION BNG PHNG PHP CHUN HAI PHA TRC TIP

Surface active agent Detergent Determination of anionic- active matter by manual or

mechanical direct two-phase titration procedure 1. Phm vi p dng Tiu chun ny quy nh phng php lc bng tay hoc khuy bng my xc nh cht

hot ng anion c trong cht ty ra. Phng php c p dng cho cc cht hot ng dng rn hoc dung dch nc. Phng php ny khng p dng khi c mt cht hot ng b mt cation Phng php lc bng tay c sp dng xc nh ankylbenzen sunfonat ; ankan

sunfonat, sunfat v hidrosunfat; ankylphenol sunfat; cc sunfat etoxi v metoxi ca ru bo; diankylsunfosuxinat v cc cht hot ng khc c cha mt nhm ho nc trong mi phn t.

Phng php khuy bng my c p dn cho tt c cc sn phm k trn nu n cho kt qu c th so snh vi kt qu nhn c theo phng php lc bng tay.

Ch thch- Cc sunfonat c khi lng phn t trung bnh thp dng hidrotrop( toluen, xilen) khng cn tr khi c mt nng nh hn 15 % ( m/m) so vi cht hot ng. mc cao hn , nh hng ca n cn c nh gi trong tng trng hp c th.

X phng, ur v cc mui ca etylendinitri-tetra axetic axit khng gy cn tr. Khi c mt cc cht hot ng b mt khng ion, nh hng ca n cn c nh gi

trong tng trng hp c th. Cc hp cht v c in hnh trong thnh phn cht ty ra nh natri clorua, sunfat, borat,

tripoliphotphat, peborat, silicat khng gy cn tr, nhng cc cht ty trng khc ngoi peborat cn c phn hu trc khi phn tch mu v mu cn th c ho tan trong nc.

2. Tiu chun trch dn TCVN 1609- 1988 Dng c thu tinh th nghim- Buret- Phn 1- Yu cu chung. TCVN 1606-1988 Dng c thu tinh th nghim- Pipet mt vch mc. TCVN 1605-1988 Dng c thu tinh th nghim- Bnh nh mc mt vch 3. Nguyn tc

Xc nh cht hot ng anion trong mi trng cha pha nc v clorofom bng cch chun vi mt th tch dung dch chun cht hot ng cation ( benzentoni clorua), c mt cht ch th l hn hp ca thuc nhum cation (dimidi bromua) v thuc nhum anion (isunfin xanh 1 )

Ch thch Qa trnh ho hc n h sau: cht hot ng anion s to mui vi thuc nhum cation tan c trong clorofom, lp ny c mu hng nh .

Trong qu trnh chun bezentoni clorua s thay th dimidi bromua trong mui v mu hng s bin khi lp clorofom khi thuc nhum chuyn sang pha nc. Lng d bezentoni clorua s to mui vi thuc nhum anion tan c trong clorofom v c mu xanh.

4. Thuc th Trong qu trnh phn tch ch s dng thuc th loi tinh khit phn tch v nc ct hoc

nc c tinh khit tng ng. 4.1. Clorofom, d20 = 1,48 g/ml c ct khong t 59,5 0C n 61,50C 4.2. Axit sunfuric, dung dch khong 245 g/l. Cn thn thm 134 ml axit sunfuric d20 =

1,83 g/ml vo 300 ml nc v pha long n 1 lit. 4.3. Axit sunfuric, dung dch chun c( H2SO4) = 1.0 mol/l 4.4. Natri hidroxit, dung dch chun c( NaOH) = 1,0 mol/l 4.5. Natri lauryl sunfat( natri odexyl sunfat) [ CH3(CH2)11OSO3Na], dung dch chun c ( C12H25NaO4S ) = 0,004 mol/l Kim tra tinh khit ca Natri lauryl sunfat v ng thi chun b dung dch chun 4.5.1 Xc nh tinh khit ca Natri lauryl sunfat Cn 5 g 0,2 g sn phm th chnh xc n 1 mg, cho vo bnh cu y trn dung tch

250 ml. Thm chnh xc 25 ml dung dch chun axit sunfuric ( 4.3), ly ng sinh hn v hi lu. T 5 n 10 pht u tin, dung dch s c dn v c xu hng to bt mnh; kim sot iu ny bng cch ngt ngun din v lc xoy bnh.

trnh to bt qu nhiu, thay v un hi lu, dung dch ny c th c t trong bp cch thu ang si trong vng 60 pht.

Sau 10 pht tip theo, dung dch s tr nn trong v ngng to bt. Tip tc un hi lu thm 90 pht na.

Ngt ngun nhit, lm ngui bnh v cn thn trng ra bnh ngng bng 30 ml etanol, sau l nc.

Thm vi git dung dch phenolphtalein ( 4.7) v chun dung dch ny bng dung dch natri hidroxit( 4.4).

Tin hnh mt php th trng bng cch chun 25 ml dung dch axit sunfuric ( 4.3 ) bng dung dch natri hidroxit( 4.4).

Tnh tinh khit t theo phn trm khi lng ca natri lauryl sunfat, theo cng thc:

28,84 x ( V1 V0 ) x CO m

Trong : V1 l th t ch dung d ch n atri hidroxit ( 4.4) s d ng cho m u tr ng, t nh b ng

mililit

V0 l th t ch dung dch natri hidroxit s dng cho phn mu th natri lauryl sunfat, tnh bng mililit;

CO l nng chnh xc ca dung dch natri hidroxit ( 4.4) tnh bng mol NaOH/l; m1 l khi lng ca phn mu th natri lauryl sunfat, tnh bng gam. 4.5.2 Chun b dung dch chun natri lauryl sunfat Cn t 1,14 g n 1.16 g natri lauryl sunfat chnh xc n 1 mg v ho tan trong 200 ml

nc. Chuyn nh lng dung dch ny vo bnh nh mc 1000 ml ( 5.3) c nt v pha long bng nc n vch mc.

Tnh nng chnh xc c2 ca dung dch bng mol C12H25NaO4S/l theo cng thc: m2 x t 288,4 x 100

Trong m2 l khi lng ca natri lauryl sunfat s dng pha dung dch, tnh bng gam: t l tinh khit nh nu trong 4.5.1. 4.6 Benzetoni clorua, dung dch chun c( C27H42ClNO2) = 0,004 mol/l Benzyl dimetyl-2-2-4(1.1.3.3 tetra metylbutyl) phenoxi-etoxietyl amoni clorua,mono

hidrat: [(CH3)3-C-CH2-C-(CH3)2-C6H4OCH2-CH2-N-(CH3)2-CH2-C6H6 ] + Cl-.H2O 4.6.1 Chun b dung dch Cn khong 1,75 g n 1,85 g bezetoni chnh xc n 1 mg v ho tan trong nc. Chuyn nh lng dung dch vo bnh nh mc 1000 ml ( 5.3) c nt thu tinh v thm n

c n vch mc Ch thch - chun b dung dch 0,004 mol/l , sy kh benzentoni clorua 105 0C, lm

ngui trong bnh ht m, cn 1,792 g chnh xc n 1 mg ho tan trong nc pha long n 1000 ml.

Cc php th chng t rng cc thuc th cation khc nh l xetyl amoni bromua v benzankoni clorua cho cc kt qu tng ng nh cc kt qu thu c khi s dng benzentoni clorua. Tuy nhin, nhng th nghim ny cha c thc hin vi s lng khng nh chc chn rng cc kt qu s nh nhau m khng ph thuc vo sn phm no c phn tch. V vy, nu benzentoni clorua khng c sn th c th dng thuc th khc, min l iu ny phi c ghi vo bin bn th. Trong trng hp c nghi ng v trng hp c tranh ci th ch c s dng bezentoni clorua.

4.6.2 Chun ho dung dch Dng pipet (5.4) ht 25 ml dung dch natri luaryl sunfat chun ( 4.5) cho vo l hoc ng

ong( 5.1) hoc bnh chun ( 5.5), ri thm 10 ml nc, 15 ml clorofom( 4.1) v 10 ml dung dch ch th hn hp( 4.8).

Chun vi dung dch benzentoni clorua( 4.6.1)/ Nu dng l hoc ng ong( 5.1) th phi y nt v sau mi ln thm phi lc k; nu dng bnh chun ( 5.5) km my khuy th chy my khuy t nht 4 giy ri tt my. Lp bn di s c mu hng. Tip tc chun v lc mnh( nu dng 5.1) hoc khuy ( nu dng 5.2). Khi tin ti im cui, nh tng c to thnh trong qu trnh lc s dn b ph v d dng. Tip tc chun tng git, lc sau mi ln thm dung dch chun cho n khi t c im cui. l thi im lp clorofom hon ton bin mt mu hng v chun sang mu xanh ghi nht.

4.6.3 Tnh nng

Tnh nng chnh xc c1 ca dung dch benzentoni clorua, biu th bng s mol C27H42ClNO2/ lit, theo cng thc: c2 x 25 V2

Trong V2 l th tch ca dung dch benzentoni clorua dng chun trong 4.6.2, tnh bng

mililit; c2 nh trong 4.5.2 4.7 Phenolphtalein,dung dch 10 g/l trong etanol Ho tan 1 g phenolphtalein trong 100 ml etanol 95 % ( V/ V). 4.8. Dung dch ch th hn hp*) 4.8.1 Dung dch gc Dung dch ny c pha t disunfin xanh 1 v dimidi bromua 4.8.1.1 Disunfin xanh 1 **)( ch s mu 42045) ( Dinatri-4,4 dinitrilodietyl triphenyl metan-2,4disunfonat) 4.8.1.2 Dimidi bromua ( 3,8- diamo- 5 metyl-6 phenyl phenantridini bromua) 4.8.1.3 Chun b dung dch gc Cn 0,5 g 0,005 g dimidi bromua( 4.8.1.2), chnh xc n 1 mg, cho vo cc dung tch 50

ml, v 0,25 g 0,005 g disunfin xanh 1( 4.8.1.1) cho vo cc dung tch 50 ml th hai. Thm khong 20 n 30 ml etanol 10% ( V / V) nng vo cc. Khuy n khi tan ht v chuyn cc dung dch vo bnh nh mc dung tch 250 ml.

Trng cc bng dung dch etanol gp vo bnh v nh mc bng etanol n vch. 4.8.2 Dung dch axit Thm 200 ml nc vo 20 ml dung dch gc ( 4.8.1) trong mt bnh nh mc dung tch

500 ml. Thm 20 ml dung dch axit sunfuric nng xp x 245 g/l ( 4.2), lc k v pha long bng nc n vch mc. G ch ti.

5.Thit b Cc thit b th nghim thng thng v 5.1 L hoc ng ong, dung tch 100 ml c nt nhm. 5.2 Buret, dung tch 25 ml v 50 ml ph hp vi TCVN 1609-1988. 5.3 Bnh nh mc mt vch, dung tch 1000 ml, c nt nhm, ph hp vi TCVN 1605-

1988 5.4 Pipet mt vch, dung tch 25 ml, ph hp vi TCVN 1606-1988 5.5 Bnh chun , c thit b khuy ph hp ( xem hnh 1) chy bng mt. 5.6 Buret t ng, kiu piston c mt, dung tch 20 ml , c chnh xc tng ng

nh qui nh trong 5.2 6.Ly mu Mu phng th nghim c chun b v bo qun ph hp vi hng dn trong cc quy

nh hin hnh. 7.Cch tin hnh

Cnh bo- Cn tun th cc quy tc an ton khi lm vic vi cc dung mi c 7.1 Phn mu th Cn mt lng mu phng th nghim( xem iu 6) chnh xc n 1 mg, vo cc 150 ml c

cha khong 0,003 mol n 0,005 mol cht hot ng anion Ch thch- Bng di y c tnh trn c s khi lng phn t trung bnh l 360, c th

c dng nh ch s s b Bng 1- Khi lng phn mu th

Lng cht hot ng trong mu, %( m/m)

Khi lng phn mu th,g Lng cht hot ng trong mu, %(m/m)

Khi lng phn mu th,g

15 10,0 60 2,4

30 5,0 80 1,8

45 3,2 100 1,4

7.2 Xc nh Ho tan phn mu th trong nc. Thm vi git dung dch phenolphtalein (4.7) v trung

ho n mu hng nht bng dung dch natri hidroxit( 4.4) hoc dung dch axit sunfuric( 4.3) nu cn.

Chuyn nh lng vo bnh nh mc dung tch 1000 ml ( 5.3) c nt nhm v pha long n vch bng nc. Lc k, dng pipet ( 5.4) ht 25 ml dung dch ny cho vo l hoc ng ong( 5.1) hoc bnh chun ( 5.5), ri thm 10 ml nc, 15 ml clorofom(4.1) v 10 ml dung dch ch th axit hn hp(4.8).

Chun bng dung dch benzentoni clorua( 4.6) nh m t trong 4.6.2, bt u t on th hai.

8. Biu th kt qu 8.1 Tnh kt qu Hm lng cht hot ng anion, biu th bng phn trm khi lng, c tnh theo cng

thc: V1 . c1 .M1 . 1000 .

100 4 . V3 . c1 .M1

m0 . 25 . 1000 =

m0 Trong V3 l th tch dung dch benzentoni clorua ( 4.6) s dng chun 25 ml dung dch

cht hot ng anion trong nc, tnh bng ml; M1 l khi lng phn t trung bnh ca cht hot ng anion; M0 l khi lng ca phn fmu tht( 7.1), tnh bng gam; C1 c xc nh trong 4.6.3. 8.2 chnh xc ca phng php 8.2.1 lp li Chnh lch gia cc kt qu t hai ln xc nh song song c tin hnh trn cng mt

mu th hoc c thc hin lin tip nhau, do cng mt ngi phn tch, s dng cng loi thit b, khng c vt qu 1,5 % ca gi tr trung bnh.

8.2.2 ti lp

Chnh lch gia hai kt qu thu c trn cng mt mu th hai phng th nghim khc nhau, khng c vt qu 3 % ca gi t5r trung bnh.

9. Bo co kt qu Bo co kt qu th bao gm nhng mc sau y; a- tt c cc thng tin cn thit nhn bit y v mu th; b- phng php s dng( theo tiu chun ny v ch r phng php lc bng tay hay

khuy bng my); c- kt qu thu c v cch biu th kt qu d- cc chi tit ca mi thao tc khng quy nh trong tiu chun ny hoc cc tiu chun

khc, hoc bt k thao tc tu no cng nh cc s c xy ra c th nh hng n kt qu.