.1OImIal of the Science of Food and Agriculture J Sci Food Agric 80:1798-1804 (online: 2000)

Abstract: Perchlorate has been identified in ground and surface waters around the USA includingsome that serve as supplies for drinking water. Because perchlorate salts are used as solid oxidants inrockets and ordnance, water contamination may occur near military or aerospace installations ordefense industry manufacturing facilities. This ion has been added to the Environmental ProtectionAgency's Contaminant Candidate List and the Unregulated Contaminant Monitoring Rule. Concernover perchlorate has prompted many residents in affected areas to switch to bottled water; however,bottled waters have not previously been examined for perchlorate contamination. Should the EPApromulgate a regulation for municipal water systems, US law requires the Food and DrugAdministration to take action on bottled water. Methods will therefore be required to determineperchlorate concentrations not only in tap water, but also in bottled waters. Ion chromatography (IC)is the primary technique used for its analysis in drinking water, but it does not provide a uniqueidentification. Confirmation by electrospray ionization mass spectrometry (ESI-MS) can serve in thiscapacity. The ESI-MS method can be applied to these products, but it requires an understanding ofmatrix effects, especially of high ionic strength that can suppress electrospray. When using methylisobutyl ketone (MIBK) as the extraction solvent, the ESI-MS method can reach lower limits ofdetection of 6ngml-1 for some bottled waters. However, dilution required to negate ionic strengtheffects in mineral waters can raise this by a factor of 10 or more, depending on the sample.Decyltrimethylammonium cation (added as the bromide salt) is used to produce an ion pair that isextracted into MIBK. After extraction, the sum of the peak areas of the ions C1oH21NMe3(Br)(CIO4)-(mlz=380) and C1oH21NMe3(CIOJi (mlz=400) is used to quantitate perchlorate. Standard additionsare used to account for most of the matrix effects. In this work, eight domestic brands and eightimported brands of bottled water were comparatively analyzed by the two techniques. For comparison,a finished potable water known to contain perchlorate was also tested. None of the bottled waters werefound to contain any perchlorate within the lower limit of detection for the IC method. Recoveries onspiked samples subjected to the IC method were ~98%.Published in 2000 for SCI by John Wiley & Sons, Ltd

Keywords: bottled water; perchlorate; ion chromatography; electrospray ionization mass spectrometry; drinkingwater

INTRODUCTIONIn 1997, perchlorate ion was found in sources ofdrinking water for much of the south western USAincluding the Colorado River .1-3 Improvements in ionchromatography for this moiety have resulted in lowerlimits of detection on the order of 5 ngml-1 (parts perbillion) and made detection possible at these sites.2-10Perchlorate has since been found in ground and

surface waters at concentrations ranging from 5 ngml-1 to 3.7mgml-1.1 It is believed that me per-chlorate is largely derived from defense and aerospaceindustry practices and military operations mat tookplace decades ago.

Perchlorate is a strong oxidant, and this behavior isobvious when hot concentrated perchloric acidtouches organic matter. Nonemeless, perchlorate

. COITespondence to: Edward T Urbansj(y, United States Environmental Protection Agency, Office of Research and Deyek)pment, National

Risk Management Research Laboratory, Water Supply and Water Resources DIvIsion, Cincinnati. OH 45268, USAE-mail: Urbansky.Edward@EPA.govt This article is a US Government work and is in the publk: domain in the USA.* Oak Ridge National Laboratory is operated under oontract by University of T ennessee-Battelle LLC for the US Department d Energy.

(R8Oeived 24 Febfuaty 2000; revised veIsiCH1 received 24 April 2000; scoept8d 31 May 2000)

Published in 2000 for SCI by John Wiley &: Sons, ud 1798

Edward T Urbans~y, 1. Baohua GU,2 Matthew L Magnuson,1 Gilbert M Brown3 andCatherine A Kelty I, Uniled States EnvIrmmen8J Prot8Cfon Agency, Offlce of ReseBICh 8M ~, Nstiona/ Risk Management R-m ~,

WsW Supply and Water R~ DIvisIon, CkJdnnatf, OH 45268, USA2En~taI Sc/encss DMskJII, Oak Ridge N8tkJn8l L8boratOIy, Oak Ridge, TN 37831, USA*3Chemic8 and AI8Iytk:a/ ScienC8S D;visIon. Oak Ridge National LabOIafOIY. Oak Ridge, TN 37831, USA*

SunJey of boulBd waun for /)I1f:h/orQte by ESI-MS

natural springs. Both brands are then purified byreverse osmosis. Other bottled waters, such asGrayson Mountain Springs, Dannon, Polar MountainWater, Evian, San Pellegrino, Naya and Perrier aretaken from specific natural springs. Both Perrier andSan Pellegrino are naturally carbonated. Some inter-nationally distributed bottled waters are taken fromspecific springs and therefore represent widespreadgeographical exposure for North American andEuropean nations, even if the products are consumedby a relatively small fraction of the population.Consumption of this nature presents cha1Ienges forrisk assessment and management. Products such asDasani and Aquafina represent a local bottler's watersource and thus a localized geographical zone ofexposure. Of course, they must be tested on a localscale as they represent the specific source for a bottlerand not for the brand overall.

EXPERIMENTAL PROCEDURESample procurement and custodyBottled waters were obtained by EPA staff. Manufac-turer seals were broken by EPA staff in the laboratory;1.2-dl portions were decanted into new polypropyleneor high-density polyethylene bottles, placed in sealedpackages to ensure chain of custody, and sent to theOak Ridge National Laboratory (ORNL) by overnightcarrier, where they were opened exclusively by ORNLstaff. Perrier and San Pellegrino were allowed tode-gas CO2 prior to use. For comparison, a perchlo-rate-tainted potable water sample (Southern NevadaWater Authority) was also subjected to the experi-mental procedure. Tested waters are listed in Table 1.

Electrospray Ionization mass spectrometric

analysesReagentsHigh purity deionized water (HP DI water) wasprepared by polishing house deionized water (reverseosmosis/UV-irradiation) with a Barnstead EasyPuresystem with organic-removal and deionizing cartridgesto obtain a resistivity ~18MQcm. The cationicsurfactant, decyltrimethylammonium bromide(CI~INMe3Br), was obtained from Fluka (Buchs,Switzerland) and prepared at O.20M (5.6gdl-l) bydissolving the solid in HP DI water. The choice ofsurfactant involves striking a balance among threemain factors: the ability form extractable ion pairs,availability of the reagent in high purity, and resistanceto forming intractable emulsions, as descnoed pre-viously.IS HPLC grade 4-methyl-2-pentanone(methyl isobutyl ketone, MIBK) was obtained fromSpectrum Quality Chemicals (San Rafael, CA, USA)and used as the extraction solvent. Ammoniumperchlorate (Aldrich, Milwaukee, WI, USA) wasprepared at 1.OOgl-1 CIO:; in HP DI water andserially diluted as necessary.

reduction is encumbered by a high activation energy,which precludes reaction under cold and diluteconditions. The chemistry of perchlorate has beenreviewed previously. 1 As a consequence of this

activation barrier, perchlorate is quite unreactive andthus long-lived under the dilute and relatively coldconditions encountered in natural bodies of water,finished potable water supplies, and in biophysiology(as when water is consumed by people or animals). Intenus of public health, perchlorate interferes withiodide uptake in the thyroid gland because the tWoanions are similar in size.1,3,11,12 The BPA NationalCenter for Environmental Assessment has undertakenstudies to determine safe levels for exposure to thiscontaminant. Meanwhile, tWo provisional action levelsof 4 and 18ngml-1, based on different assumptionsused in the original toxicology studies, remain in force.

At present, the BPA Office of Water has notestablished a national primary drinking water standardfor perchlorate; however, this ion has been added tothe Contaminant Candidate List (CCL)13.14 and theUnregulated Contaminants Monitoring Rule(UCMR).15 If the BPA promulgates a drinking waterregulation, the Food and Drug Administration (FDA),will be required to act on bottled water, pursuant to 21USC 349. Newspaper accounts have suggested thatmany people in areas with perchlorate-contaminateddrinking water have switched to bottled water,although bottled waters have not so far been testedto our knowledge.

Previously, we reported on the determination ofperchlorate in drinking water using electrosprayionization mass spectrometry (ESI-MS).16-19 Per-chlorate anion may be extracted into organic solventsusing surfactant cations, especially aikyltrimethylam-monium ions (eg decyl, lauryl, myristyl or cetyl).17-19Other investigators also report quantitation of per-chlorate by mass spectrometric methods.20-23 In thiswork, we examine the application of this approach aswell as the ion chromatographic method to ten brandsof bottled water. Ion chromatography can be a usefulscreening tool. If a sample is chromatographed and nopeak is observed, a fortified sample can be tested. Ifrecovery of the spike is satisfactory, there is reasonableassurance that the analyte is not present. One of theweaknesses of any chromatographic method is thatidentification by retention time is not necessarilyunique. Confirmatory testing can be accomplishedeffectively by mass spectrometry because of the massof the ion and the resulting m/z ratio. Isotopic ratiosbased on relative abundance (in this case 35CI vs 37 CI

with a 3:1 ratio) provide additional evidence that theidentification is correct.

Bottled waters can vary significantly in ionicstrength, salt composition and dissolved gas content(mainly carbon dioxide). Like municipal potable watersupplies, bottled waters vary in treatment techniques,including disinfection. Some bottled waters, such asPepsi's Aquafina or Coca-Cola's Dasani are derivedfrom local sources - either municipal tap water or

1SdPO()(lAgric 80:1798-1804 (online: 2000) 1799

ET UrlJansky et al

Table 1. Waters ex8ninecl in this study

ScxNceCaIf'BrIy, addressBrand

Apoilinaris Naturally Sparkling Spring Water Liberty Richter (distributor), Saddle Brook, NJ 07663, USA Germany

Aquafina PepsiCo bottler was Warrenton Products Inc, Warrenk)n, Varies by locationMO 63383, USA

Crystal Geyser Natural Spring Water CG Roxane LP, POBox 249, Benton, TN 37307, USA CG Roxane

Dannon Danoon National Spring Water, 208 Harbor Drive, Stamford, Spring Piedmont,CT 06902, USA Quebec, Canada

Dasani The Coca-Goia Co. Atlanta, GA, USA Varies by location

Eureka Springs All Natural Spring Water SaegertONn Beverages, Saegertown, PA 16433, USA Municipal tap

Evian SA Evian Co, Evian-les-Bains, France Cachet Spring

Fountainhead Natural Spring Water Fountainhead, White Water Falls Rd, Oconee, SC, USA Sumter Natural Forest

Gerolsteiner Natural Mineral Water Gerolsteiner Brunnen GmbH & Co, GerOistein springD-54567 GerolsteinNulkaneifel, Germany (near Rhine, Moselle)

Grayson Mountains Grayson Mountain Water Co, Independence, VA, USA Local springNaya Nora Beverages Inc, Mirabel, Quebec, JOV1Z0, Canada Local springS Pellegrino San Pellegrino, Italy Local springPerrier Perrier, Vergeze, France Local spring

Poland Spring Natural Spring Water Poland Spring Water Co, Poland, ME 04274, USA Local spring

Polar Mountain Spring Water Crystal Springs Water Co, Mableton, GA 30059, USA Crystal Spring,Blue Ridge, GA

Southem Nevada8 Water Authority Las Vegas, NV, USA Lake Mead onColorado River

Volvic Natural Spring Water Danone Group, Ste VoMc, at VoMc 63500. France Clairvic Spring. 5I'tNA.. fiIWh8d /X)1ab18 water ~ a mIIk:ipai ~-~ 8 boWed~. It. UI8d b"~ _It 18 ~ tI coIUin perc~al8 m.

quadrupole mass spectrometer (Q3) with a Finnegan-Mat electrospray interface apparatus was used foranalysis. A Waters (Milford, MA, USA) MS-600pump delivered pesticide residue analysis grademethanol (Burdick & Jackson, Baxter Healthcare,Muskegon, MI, USA) as the carrier; sheathing gaspressure was 480kPa (70 psi); capillary temperaturewas 200°C; spray potential was 4.0kV.

ExtractionThe following were quantitatively added to a 100-mlvolumetric flask: 96.0ml of the test water sample,1.0ml ofO.20M C1O~INMe3Br (aquesus), and 5.0mlof MIBK. The rationale for this procedure is fairlystraightforward. The presence of small water dropletscannot be tolerated in the ESI-MS analysis. Aseparatory funnel will not work because MIBK is lessdense than water (coming out second); thus, residualwater droplets left on the funnel will be carried along inthe MIBK layer. Because of the large volume of waterto MIBK, a 40-ml vial, such as that used for manyEPA drinking water methods also will not work. Theadvantage to a 100-ml volumetric flask is that thesolvent is constrained to the neck, where it is readilydrawn off once the extraction is complete. Weemphasize that the flask is not used in its volumetriccapacity, but merely as a convenient vessel forrecovering the extraction solvent. Duplicate sampleswere run with the following fortifications (spikes): 0(unspiked), 10, or 20ngml-1 CIOi. As a blank,unspiked samples of the bottled waters were extractedwithout the surfactant. The blank correction proce-dure has been explained previously.lS,19 Due tolimited sample volume of the first lot, Perrier and SPellegrino were not run in duplicate; however, anotherlot was tested in duplicate.

Ion chromatographic analysesSamples were analyzed at ORNL as received fromEPA following the method reported by Jackson et aL 8

Dionex (Sunnyvale, CA, USA) AG 11 guard and ASIIanalyrical columns were used on a Dionex DX-500 ionchromatograph for these analyses. In addition to thetest water samples, spiked samples containing 10 and20ngml-1 CIO; were run to verify performance.

RESULTS AND DISCUSSIONESI-MS data analysisTo correct for od1er species that form ions wid1 m/zequal to d1at of d1e analyte ions, d1e peak areasobtained for an MIBK extract wid1out detergent weresubtracted from d1ose extracted wid1 d1e cationicsurfactant. Perchlorate forms complexes wid1 d1esurfactant cation of d1e form C1O~INMe3(Br)(CIO4)- (m/z =380) and C10H21NMe3(CIO~2(m/z =400). When extracted wid1 dichloromethane,municipal potable water samples showed linear

InstrumentationA Finnigan-Mat (San Rafael, CA, USA) TSQ 700

1100 J SdFoodAgric 80:1798-1804 (online: 2000)

Surwy of /)ottJ.J V1QU1f for P'7'I:/I/orrIte by ESI-MS

25

20

i15

80010

}<C 5

0-10 -5 0 5 10 15 20 25

Perchlorate concentration (ng mt1)

Fig... 2. StarKlard ~ition p~ for (0) Aquaflna. (6) Naya. and (V)SNWA taT! ESI-MS analysis. The sum of the blank~ pe8t'-for ntzs380 and 400 88 p~ against the added peroN«*~Iration (~ic8e spikes at 10 and 2Ong~~I). The ~r8Pf888nIs the conc:enIr8lion ~ ~ in the S8nple.

Flgu" 1. Negative ion ESI-MS injectk)n peaks ffX Soothem Nevada WaterAu~ty finished ~. a s~plY knCPNn to contain perdiklr8le. The ~ankval~ is ootained ~ surfactant (no C1aH21NMe;). Along wiIh the~ su~. standard additions of 10 and 2Ongml-1 .. u88d to8XtIapoIate to the perchkwate oorK:antralion in the watar. Two ions are ~to ~ the pen:h1oral8: C10H21NMa,(Br) (ClOO> (niz=380) arxlC1oH21NMe,(ClOJ2 (niz-400). Nd8 that perchlorale ~ntration isreIaEd to peek 8'88 aid not paek haighl The refatk)nship between<XM1C8IIb'ation (~ of anaiyte injad8d) 81d P8'* - is notInvnadal8iy 8Y-.nt ~ of the shape of the paeks. and integrated- must be U88d. Nearty all (>90%) of the ~ is 8Xb'ad8d intothe solvent tII8 first time as shown by ~ ~.

increase in peak area with perchlorate concentra-tion.18,19 For this work, however, MIBK was chosen asthe solvent to minimi7.e exposure of laboratorypersonnel to chlorinated solvents in keeping withEPA's goals of laboratory safety in test methoddevelopment. Partitioning and ionization of the ionpairs in MIBK is reduced relative to methylenechloride. This proceduce is sufficient for the purposesof quantitation, but it requires more careful treatmentof the raw data. The difference in partitioning isheightened in waters of higher ionic strength becausethere is more competition for the decyltrimethyl-ammonium ion. The best results are obtained bysumming the areas of the two ions, C1~lNM~(Br)(ClOJ- and C1oH21NMe3(ClO4)2. While it may bepossible to mitigate the effect by using more surfac-tant, there is a significant risk of forming emulsionsand the latter approach was not explored.

Figure 1 shows the flow injection peaks observed fora water known to contain perchlorate (SNWA).Making standard additions and monitoring the sumof the peak areas at m/z=380 and 400, we thenextrapolated to the abscissa. This gives the concentra-tion of perchlorate in the sample in a reasonablystraightforward fashion (Fig 2).

Analytical resultsPerchlorate was found only in the water sample fromthe Southern Nevada Water Authority. The concen-tration of the ion obtained using IC and ESI-MSmethods agreed within the limits of experimentalerror. None of the bottled waters tested containedperchlorate above the lower limit of detection reportedfor the IC method, 5ngtnI-1. The IC method is wellestablished8 and straightforward. Chromatograms forAquafina and Naya are shown in Fig 3; recovery isexcellent as shown by the chromatograms of thefortified samples. For all of the waters, recovery ofthe spike by IC was >98%. Perchlorate was notdetected in any brand of water. For comparison, Fig 4

shows chromatograms for SNW A finished waterunspiked and spiked with 10ngml-1 CIO;.

Least squares parameters for the standard additionsused in the ~I-MS method are summarized forbottled waters in Table 2. The ESI-MS methodcorroborates the IC result obtained for the SNW Asample. For the non-carbonated bottled waters, theESI-MS results are consistent with the IC findings thatperchlorate is below the lower limit of detection, ofapproxilnately 5 ngml-1. The two naturally carbo-nated waters show a curious effect: positive abscissalintercepts, which correspond to negative analyteconcentrations. This non-sensical result is caused bythe high ionic strength of these waters. Although theywere de-gassed prior to analysis to remove CO2, theycontain high levels of dissolved inorganic salts. Highionic strength interferes with electrospray iomzation;accordingly, signal intensity is diminished. Thisproduces a negative peak relative to the backgroundsignal of the methanol carrier, which has an ionicstrength approaching zero. In some cases, the problemcan be eliminated by diluting the sample; however, thelower limit of detection is raised by a factor equal to thedilution factor. Consequently, there is a trade-off to bemade, and thorough characterization of the matrix isrequired to apply this method optimally to waters withhigh ionic content. Even with 10% v/v dilutions, wewere unable to successfully quantitate trace perchlo-rate in Perrier, Pellegrino, or several other sparklingmineral waters that contain high levels of dissolvedinorganic salts (positive x-intercepts were obtained forall). Although perchlorate concentrations ?200ngml-1 can be quantitated in mineral waters, this haslittle practical application.

The lower limit of detection (il..OD) for the ~I-MS method using MIBK is 6ngml-1, based on DIwater standards run at 0, 1.0, 2.0, 4.0, 6.0, 8.0 and

180]J sa FoodAgric 80:1798-1804 (online: 2000)

ET U7baJU}y et al

Figure 3. Ion chromatQ9'8ns fa"OOtIJed water samples that oontain 00perchk>late: (a) Aquafina wwJ (b) Naya.Ch~rams fa" the -.TIe S8mpIe8fortified with 1 0 ng ml ~ 1 perci1k1rae:

(c) Aquafina and (d) Naya.

samples. However, the ESI-MS method cannot readilybe used for beverages such as fruit juices or wines or forseawater.

Applicability and conclusionsWhile IC is likely to be the predominant technique fordetermining perchlorate ion concentration in raw andfinished drinking waters (including bottled waters),ESI-MS provides a useful means of confirming the ICidentification, which is based on retention time alone.Capillary electrophoresis or Raman scattering spectra-me~4,25 may one day playa similar role, but thesetechniques are currently not sensitive enough withoutpre-concentration (eg with an anion exchange resin orsample stacking). ESI-MS may be applied to a varietyof drinking water matrices as a confirmatory techniqueto support identifications made by IC. It is reasonablyrugged and reproducible while requiring a minimumof sample preparation and no separation step prior toanalysis. As with the IC method, high levels of

10.Ongml-l. Eight replicates at 6.0ngml-1 gave anestimated standard deviation of 0.2ngml-l. Thisleads to an EPA method detection limit (MDL) of0.7 ngml-1 (using Student's t = 3.500 for the 99%confidence interval and seven degrees of freedom).However, a threshold signal distinguishable from theblank does not occur below 5ngml-l, and so we feel aminimum reporting level of 5-6ngml-1 is the mostappropriate.

In addition to the possloility of electrospray sup-pression, it is worth noting that samples of very highionic strength may suffer from a limiting reagentproblem. The post-mixing concentration of thecationic surfactant is 2.0D1M; thus, competition amonganions for the surfactant must be considered. This isparticularly true for less-hydrated anions, such asnitrate or bromide, which are extracted into theMIBK, paired wim the surfactant cation. Competitionfor me surfactant - to the point of adversely affectingthe analysis - is uncommon with potable water

1802 , &;i FoodAgric 80:1798-1804 (online: 2000)

Sun;rcy of boaW -.n for pen;hlorau by ESI-MS

csIcd [C/Oilb(nJIng-1)

Slope-(counts mlng-1)

y-intercept(counts)Water

11500%4007200%30088X>%2007400%100~%6009800%8009700%500

10CXX>% 700

5!XX>%200

15000%900029 <XX> % 6000

2000%4000

9000%2000

11 <XX>% 13<XX>

7<XX>% 15<XX>

3Q<XX>% 10<XX>

15 <XX> % 15<XX>

54 <XX> % 5(XX)

1.3:'0.&00.1*1°0.2*°.5"12:.0.~1.3:.1.~O.7~1.~

3~1c1.4~1.4c9.2:'0.8

AquafinaCannonCasaniEureka SpringsEvianGrayson MountainsNayaPolarSNWA. ~ were caclAaIed based 00 the SIm of the - b' rrtz - ~ Md 400. Each ~ is based on

duplicale Jx)jrD at 0, 10, ~ngm-1 added perchlaoate.b The perc~e caw:en1ralion is ~ 86 !he addiliw imlelSe 01 the x-intercept in the method 01

sl8ndard addllklns.

c~LLODof6.0ngml-1.Table 2. ESI-MS results obtained fa' amenab8

I888d balded wMers and SNWA water

reduction of perchlorate has beep observed in thelaboratory,29,30 it has not yet been definitively ob-served in me environment. Consequently, contami-nated sites may remain in that condition for decades.Until such time as natural attenuation can be demon-strated or source water protection can be assured, itwill be necessary continually to assess natural watersources and finished potable water for this ion.

ACKNOWLEDGEMENTSWe thank Peggy Roefer and Kay Brothers of theSouthern Nevada Water Authority for providingsamples of finished potable water from their facility.

dissolved salts also affect me ESI-MS method,primarily by reducing the eleCtroSpray efficiency.Almough we did not specifically try to overcome meproblems posed by high CO2/HCO; concentrations,we suspect that careful acidification could help reducethese. Previously, we have found mat moderate aceticacid concentrations (~O.l mM) did not advserselyaffect ionization or detection.l~lS

Once me matrix effects have been dealt with, it ispossible to run a large number of samples quickly, aseach sample requires only a few minutes of instrumenttime. Although the drinking water industry hascharacteristically relied on ion chromatography formeasurement the concentration of ions, many labora-tories (especially research laboratories) have quadru-pole mass spectrometers and electrospray introductionis increasingly popular. ESI-MS thus becomes onemore technique in the arsenal of analytical weapons tobe used with d~ water matrices. This isparticularly important because IC is the only othertechnique that can be readily applied to low-levelcontamination. It is particularly significant that ESI-MS and IC are fundamentally different techniques.Accordingly, one can have higher confidence in ameasured concentration when results from dissimilartechniques agree than in the agreement of retentiontime on different chromatography columns. In thecase of a particularly problematical sample, eluatefractions can be collected from me IC and thensubjected to ESI-MS; however, this requires collectingthe peak from a considerable number of runs. Inmatrices with higil concentrations of interferinganions, the collected fractions can be reinjected. Wehave applied such a process to the measurement ofperchlorate in the wood of salt cedar growing inperchlorate-contaminated regions.26

With the popularity and worldwide availability ofmany brands of bottled water, purity is a globalconcern. With any source water, there is a possibility ofexposure to perchlorate through run-off from ord-nance installations or agricultural fields fertilized withnatural Chile saltpeter?7.2S Although microbiological

REFERENCES1 Urbansky ET, Perd11orate chemimy: implications for analysis

and remediation. Bior8m J 2:81-95 (1998) and referencestherein.

2 Urbansky ET and Schock MR, Issues in managing the risksassociated with perchlorate in drinkina water. J EmJiron Manag56:79-95 (1999) 8nd references therein.

3 Damian P and Pontius FW, From rockets to remediation: theperd11orate problem. EmJiron 1+ot 10:24-31 (1999).

4 California Department of Health Services, Sanitation andRadiation Laboratories Branch, DetemIinaIiOII of Perchlorateby Ion Chromatography, Rev O. Jun 3, 1997.

5 Harrington P and Shen Y, Improved analysis of perd1lorate inwater, Proc Water Qual Technol Co1!/; A WW A, San Dicao, CA,Nov 1--4, 1998, 1405-1412 (CD-ROM).

6 Win K. Laikhtman M, Robm J and Jackson FE, Low levelperchlorate analysis in drinking water 8nd ground water by ionchromatography. Am EmI Lab 10:1 (1998).

7 Eaton A, Hagbani A, Cox N and Wong E, Proc Water QualTechnol Con!, AWWA, San Diego, CA, Nov 1--4,1998,1413-1423 (CD-ROM).

8 Jackson FE, Laikhtman M and Rohrer JS, Determination of tracelevel perchlorate in drinking 8nd ground water by ionchromatography. J ChromatogrA 850:131-135 (1999).

9 Jackson FE, Gokhale S and Robm JS, Chapter 2. Recentdevel~ents in the analysis of perchlorate by ion chroma-tography, in Perchlorate m the Envinmmmt, Urbansky ET,Kluwer/Plenum, New York, NY, USA (2000).

10 Tsui DT, Clewell RE, Eldridge IE and Mattie DR, Chapter 7.Perd11orate analysis with the AS 16 separation eolumn, in

1803J Sci FoodAgric 80:1798-1804 (online: 2000)

ET Ur6ansky et al

mobility spectrometry!mass spectrometry. Appl Spearosc53:1367-1374 (1999).

21 Barnett DA and Horlick G, Quantitative electroapray massspectrometry of halides and halogenic anions. J Anal AtSpearom 12:497-501 (1997).

22 oewen RE, Olaudhuri S, Dickson S, Cassady RS, Wallner WN,Eldridge IE and Tsui DT, Olapter 6. Analysis of trace levelperchlorate in driDkina water and ground water by elec:ttospraymass spectrometry, in Pen:hlomte in the EntIinmmmt, ed byUrbansky ET, KJuwer/Plenum, New York, NY, USA (2000).

23 Koester CI, Bdler HR and Halden RU, Analysis of perchloratein groundwater by electrospray ionization mass spectrometry!mass spectrometry. EmJinmSci TechIIOl34:1862-1864 (2000).

24 Kowalchyk WK. Walker PAm and Morris MS, Rapid normalRaman spectroSCOpy of sub-ppm oxy-anion solutions: the roleof elecaophoretic preconcentration. Appl Spectrosc 49: 1183-1188 (1995).

25 Miller AG and Macklin IA, Matrix effects on the Ramananalytical lines of oxyanions. Anal Ghent 52:807-812 (1980).

26 Urbansky ET, Magnuson ML, Kelty CA, Brown SK. Per-chlorate uptake by salt cedar (Tamarix _sissima) in the LasVegas Wash riparian ecosystem. sci TOt BII!JiMI 256:227-232

(2000).27 Schilt AA, Perchloric Acid and Perchlorates. GFS Chemicals,

Columbus, OH, USA, pp 3-4 (1979) and references therein.28 Susarla S, Collette TW, Garrison A W, Wolfe NL and

McCutcheon SC, Perchlorate identification in fertilizers.BmIiroII sci TechIIOl 33:3469-3472 (1999) and referencestherein; see also correction EmJiron Sci Technol34:224 (2000).

29 Logan BE, A review of chlorate- and perchlorate-respiringmicroorganisms. B~ J 2:69-78 (1998) and referencestherein.

30 Coates ID, Michaelidou U, Broce RA, O'Connor SM. CrespiJNand Achenbach LA, The ubiquity and diversity of dissim-ilatory (per)chlorate-reducing bacteria. Appi Env Microbiol65:5234-5241 (1999).

Pm:hlorau in the Em7irrmmmr, ed by Urbansky ET, KIuwer/Plenwn, New York, NY, USA (2000).

11 Wolff 1, PerclI)orate and the thyroid gland. J¥JamI &m 50:89-105 (1998).

12 ClarkJ, Chapter 3. Toxicology of perchlorate, inPercllJOfOauin theE1If1irl)llJllellt, ed by Urbansky ET, KIuwer/PImum, New York,NY, USA (2000).

13 Perciasepe R, Part m. Environmmtal Protection Agency.Announcement of the drinking water contaminant candidatelist; notice. Fed &gist 63: 10273-10287 (1998).

14 Drinking Water Contaminant Candidate List, Feb 1998, EPADoc No 815-F-98-002.

15 Browner C, Part II. Environmental Protection Agency, 40 CPRpans 9, 141 and 142, Revisions to unregulated contaminantmonitoring regulation for public water systems; final rule. Fed&gist 64:50555-50620 (1999).

16 Urbansky ET, Magnuson ML, Freeman D and Jelks C,Quantitation of perchlorate ion by electrospray ionizationmass spectrometry (ESI-MS) using stable association com-plexes with organic cations and bases to enhance selectivity. JAna/At Spearom 14:1861-1866 (1999).

17 Urbansky ET and Magnuson ML, Chapter 8. Smsitivity andselectivity enhancemmt in perchlorate anion quantitationusing complexation-eleClrospray ionization-mass SpectroIDe-ny, in Pen;h/onIu in the EmIinmment, ed by Urbansky ET,KIuwer/Plmum, New York, NY, USA (2000).

18 Magnuson ML, Urbansky ET and Kelty CA. Detennination ofperchlorate at trace levels in drinking water by ion-pairextraction with eleClrospray ionization mass Spectromeny.Anal ChmI 71:25-29 (2000).

19 Magnuson ML, Urbansky ET and Kelty CA. Microscaleextraction of perchlorate in drinking water with low leveldetection by e1ectrospray-mass spectrometry. Talanta SZ:285-291 (2000).

20 Barnett DA. Guevremont R and Purves RW, Determination ofpans..per-ttiUion levels of chlorate, bromate, and iodate byelectrospray ionization/high-field asymmetric wavefonn ion

1804 , Sci Food Agric 80:1798-1804 (online: 2000)

Lynne HaberThursday, May 01, 2003 11 :58 AMMeg PoehlmannCopper Phase II

From:Sent:To:Subject:

Meg,

Could you please take care of the rest of getting the paper resubmitted?

All of the files you need are on the server: Project files\copper\Publications Phase II\Resubmitted-post peerreview.

This is what I need:

Print out the cover letter (coverlet) on letterhead for me to sign.The package to the publisher includes:Two hard copies of the revised manuscript (Copper phase II-revised)Two hard copies of the response to comment (Copper phase II-response to reviewers)A diskette with the revised manuscript.

Please also print a clean coppy of the revised manuscript for the files (I think you keep submitted papers downthere, rather than with project files?)Please send regular mail.

I'd love to get this out today, but it can wait until Friday if you're swamped.

Celebrate when this goes out!!

Scott has cut us off on funding for this, given the history, so this isn't income generating. I'd prefer that youmark it as admin or professional development (you're contributing to a nonprofit - TERA). However, if you feelstrongly that this should be billable, you can do the same thing I'm doing - marking to director's developmental

reserve (my way of having Mike take some responsibility for the history here.)

Thank you!!

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