METHOD Revision 1.0. D.J. Munch (USEPA, Office of Water) and D.P. Hautman (International Consultants, Inc.) - Method 551.

Transcription

1 METHOD DETERMINATION OF CHLORINATION DISINFECTION BYPRODUCTS, CHLORINATED SOLVENTS, AND HALOGENATED PESTICIDES/HERBICIDES IN DRINKING WATER BY LIQUID-LIQUID EXTRACTION AND GAS CHROMATOGRAPHY WITH ELECTRON-CAPTURE DETECTION Revision 1.0 J.W. Hodgeson, A.L. Cohen - Method 551, (1990) D.J. Munch (USEPA, Office of Wter) nd D.P. Hutmn (Interntionl Consultnts, Inc.) - Method 551.1, (1995) NATIONAL EXPOSURE RESEARCH LABORATORY OFFICE OF RESEARCH AND DEVELOPMENT U.S. ENVIRONMENTAL PROTECTION AGENCY CINCINNATI, OHIO

2 METHOD DETERMINATION OF CHLORINATION DISINFECTION BYPRODUCTS, CHLORINATED SOLVENTS, AND HALOGENATED PESTICIDES/HERBICIDES IN DRINKING WATER BY LIQUID-LIQUID EXTRACTION AND GAS CHROMATOGRAPHY WITH ELECTRON-CAPTURE DETECTION 1.0 SCOPE AND APPLICATION This method is pplicble to the determintion of the following nlytes in finished drinking wter, drinking wter during intermedite stges of tretment, nd rw source wter. The prticulr choice of nlytes from this list should be function of the specific project requirements. Anlyte CAS No. Disinfection Byproducts (DBPs): Trihlomethnes Chloroform Bromodichloromethne Bromoform Dibromochloromethne Hlocetonitriles Bromochlorocetonitrile Dibromocetonitrile Dichlorocetonitrile Trichlorocetonitrile Other DBPs Chlorl Hydrte Chloropicrin ,1-Dichloro-2-propnone ,1,1-Trichloro-2-propnone Chlorinted Solvents: Crbon Tetrchloride ,2-Dibromo-3-chloropropne [DBCP] ,2-Dibromoethne [EDB] Tetrchloroethylene ,1,1-Trichloroethne ,1,2-Trichloroethne Trichloroethylene ,2,3-Trichloropropne Pesticides/Herbicides: Alchlor Atrzine Bromcil Cynzine Endrin

3 Anlyte CAS No. Endrin Aldehyde Endrin Ketone Heptchlor Heptchlor Epoxide Hexchlorobenzene Hexchlorocyclopentdiene Lindne (gmm-bhc) Metolchlor Metribuzin Methoxychlor Simzine Triflurlin This nlyte list includes 12 commonly observed chlorintion disinfection 3,4 byproducts, eight commonly used chlorinted orgnic solvents nd 16 hlogented pesticides nd herbicides. 1.3 This method is intended s stnd-lone procedure for either the nlysis of only the trihlomethnes (THMs) or for ll the chlorintion disinfection byproducts (DBPs) with the chlorinted orgnic solvents or s procedure for the totl nlyte list. The dechlorintion/preservtion technique presented in Section 8.0 detils two different dechlorinting gents. Results for the THMs nd the eight solvents my be obtined from the nlysis of smples employing either dechlorinting gent. (Section 8.1.2) 1.4 After n nlyte hs been identified nd quntitted in n unknown smple with the primry GC column (Section ) qulittive confirmtion of results is strongly recommended by gs chromtogrphy/mss spectrometry 10,11 (GC/MS), or by GC nlysis using dissimilr column (Section ) The experimentlly determined method detection limits (MDLs) for the bove listed nlytes re provided in Tbles 2 nd 8. Actul MDL vlues will vry ccording to the prticulr mtrix nlyzed nd the specific instrumenttion employed. 1.6 This method is restricted to use by or under the supervision of nlysts experienced in the use of GC nd in the interprettion of gs chromtogrms. Ech nlyst must demonstrte the bility to generte cceptble results with this method using the procedure described in Section Methyl-t-butyl ether (MTBE) is recommended s the primry extrction solvent in this method since it effectively extrcts ll of the trget nlytes listed in Section 1.1. However, due to sfety concerns ssocited with MTBE nd the current use of pentne by some lbortories for certin method nlytes, pentne is offered s n optionl extrction solvent for ll nlytes except

4 chlorl hydrte. If project requirements specify the nlysis of chlorl hydrte, MTBE must be used s the extrcting solvent. This method includes sections specific for pentne s n optionl solvent. 2.0 SUMMARY OF METHOD 2.1 A 50 ml smple liquot is extrcted with 3 ml of MTBE or 5 ml of pentne. Two µl of the extrct is then injected into GC equipped with fused silic cpillry column nd linerized electron cpture detector for seprtion nd nlysis. Procedurl stndrd clibrtion is used to quntitte method nlytes. 2.2 A typicl smple cn be extrcted nd nlyzed by this method in 50 minutes for the chlorintion by-products/chlorinted solvents nd two hours for the totl nlyte list. Confirmtion of the eluted compounds my be obtined using dissimilr column (Section ) or by the use of GC-MS. Simultneous confirmtion cn be performed using dul primry/confirmtion columns instlled in single injection port (Section 6.9.3) or seprte confirmtion nlysis. 3.0 DEFINITIONS 3.1 Internl Stndrd (IS) -- A pure nlyte(s) dded to smple, extrct, or stndrd solution in known mount(s) nd used to mesure the reltive responses of other method nlytes nd surrogtes tht re components of the sme smple or solution. The internl stndrd must be n nlyte tht is not smple component. 3.2 Surrogte Anlyte (SA) -- A pure nlyte(s), which is extremely unlikely to be found in ny smple, nd which is dded directly to smple liquot in known mount(s) before extrction or other processing nd is mesured with the sme procedures used to mesure other smple components. The purpose of surrogte nlyte is to monitor method performnce with ech smple. 3.3 Lbortory Duplictes (LD1 nd LD2) -- Two smple liquots, tken in the lbortory from single smple bottle, nd nlyzed seprtely with identicl procedures. Anlyses of LD1 nd LD2 indicte precision ssocited with lbortory procedures, but not with smple collection, preservtion, or storge procedures. This method cnnot utilize lbortory duplictes since smple extrction must occur in the smple vil nd smple trnsfer is not possible due to nlyte voltility. 3.4 Field Duplictes (FD1 nd FD2) -- Two seprte smples collected t the sme time nd plce under identicl circumstnces nd treted exctly the sme throughout field nd lbortory procedures. Anlyses of FD1 nd FD2 give mesure of the precision ssocited with smple collection, preservtion nd storge, s well s with lbortory procedures. Since lbortory duplictes

5 cnnot be nlyzed, the collection nd nlysis of field duplictes for this method is criticl. 3.5 Lbortory Regent Blnk (LRB) -- An liquot of regent wter, or other blnk mtrix, tht is treted exctly s smple including exposure to ll glsswre, equipment, solvents, regents, internl stndrds, nd surrogtes tht re used with other smples. The LRB is used to determine if method nlytes or other interferences re present in the lbortory environment, the regents, or the pprtus. 3.6 Field Regent Blnk (FRB) -- Regent wter, or other blnk mtrix, tht is plced in smple continer in the lbortory nd treted s smple in ll respects, including shipment to smpling site, exposure to smpling site conditions, storge, preservtion nd ll nlyticl procedures. The purpose of the FRB is to determine if method nlytes or other interferences re present in the field environment. 3.7 Lbortory Fortified Blnk (LFB) -- An liquot of regent wter, or other blnk mtrix, to which known quntities of the method nlytes re dded in the lbortory. The LFB is nlyzed exctly like smple, nd its purpose is to determine whether the methodology is in control, nd whether the lbortory is cpble of mking ccurte nd precise nlyte quntittion t vrious concentrtions including the required method detection limit. 3.8 Lbortory Fortified Smple Mtrix (LFM) -- An liquot of n environmentl smple to which known quntities of the method nlytes re dded in the lbortory. The LFM is nlyzed exctly like smple, nd its purpose is to determine whether the smple mtrix contributes bis to the nlyticl results. The bckground concentrtions of the nlytes in the smple mtrix must be determined in seprte liquot nd the mesured vlues in the LFM corrected for bckground concentrtions. 3.9 Stock Stndrd Solution (SSS) -- A concentrted solution contining one or more method nlytes which is prepred in the lbortory using ssyed reference mterils or purchsed s certified from reputble commercil source Primry Dilution Stndrd Solution (PDS) -- A solution of severl nlytes prepred in the lbortory from stock stndrd solutions nd diluted s needed to prepre clibrtion solutions nd other needed nlyte solutions Clibrtion Stndrd (CAL) -- A solution prepred from the primry dilution stndrd solution or stock stndrd solutions nd the internl stndrd(s) nd surrogte nlyte(s). The CAL solutions re used to clibrte the instrument response with respect to nlyte concentrtion Qulity Control Smple (QCS) -- A solution of method nlytes which is used to fortify n liquot of LRB or smple mtrix. The QCS is obtined from

6 source externl to the lbortory nd different from the source of clibrtion stndrds. It is used to check lbortory performnce with externlly prepred test mterils Lbortory Performnce Check Solution (LPC) -- A solution of selected method nlytes, surrogte(s), internl stndrd(s), or other test substnces used to evlute the performnce of the instrument system with respect to defined set of method criteri Method Detection Limit (MDL) -- The minimum concentrtion of n nlyte tht cn be identified, mesured nd reported with 99% confidence tht the nlyte concentrtion is greter thn zero. (Appendix B to 40 CFR Prt 136) 3.15 Estimted Detection Limit (EDL) -- Defined s either the MDL or level of compound in smple yielding pek in the finl extrct with signl to noise (S/N) rtio of pproximtely five, whichever is greter Procedurl Stndrd Clibrtion -- A clibrtion method where queous clibrtion stndrds re prepred nd processed (e.g., purged,extrcted, nd/or derivtized) in exctly the sme mnner s smple. All steps in the process from ddition of smpling preservtives through instrumentl nlyses re included in the clibrtion. Using procedurl stndrd clibrtion compenstes for ny inefficiencies in the processing procedure. 4.0 INTERFERENCES 4.1 Impurities contined in the extrcting solvent usully ccount for the mjority of the nlyticl problems. Ech new bottle of solvent should be nlyzed for interferences before use. An interference free solvent is solvent contining no peks yielding dt t MDL (Tbles 2 nd 8) t the retention times of the nlytes of interest. Indirect dily checks on the extrcting solvent re obtined by monitoring the lbortory regent blnks (Section 9.3). Whenever n interference is noted in the regent blnk, the nlyst should nlyze the solvent seprtely to determine if the source of the problem is the solvent or nother regent. 4.2 Glsswre must be scrupulously clened. Clen ll glsswre s soon s 13 possible fter use by thoroughly rinsing with the lst solvent used in it. Follow by wshing with hot wter nd detergent nd thoroughly rinsing with tp nd regent wter. Drin dry, nd het in n oven or muffle furnce t 400 C for one hour. Do not muffle volumetric wre but insted rinse three times with HPLC grde or better cetone. Thoroughly rinsing ll glsswre with HPLC grde or better cetone my be substituted for heting provided method blnk nlysis confirms no bckground interfernt contmintion is present. After drying nd cooling, sel nd store ll glsswre in clen environment free of ll potentil contmintion. To prevent ny ccumultion of dust or other contminnts, store glsswre inverted on clen luminum foil or cpped with luminum foil

7 4.3 Commercil lots of the extrction solvents (both MTBE nd pentne) often contin observble mounts of chlorinted solvent impurities, e.g., chloroform, trichloroethylene, crbon tetrchloride. When present, these impurities cn normlly be removed by double distilltion. 4.4 This liquid/liquid extrction technique efficiently extrcts wide boiling rnge of non-polr nd polr orgnic components of the smple. Thus, confirmtion is quite importnt, prticulrly t lower nlyte concentrtions. A confirmtory column (Section ) is suggested for this purpose. Alterntively, GC/MS my lso be used for confirmtion if sufficient concentrtion of nlyte is present. 4.5 Specil cre must be tken in the determintion of endrin since it hs been reported to brekdown to ldo nd keto derivtives upon rection with ctive 14 sites in the injection port sleeve. The ctive sites re usully the result of micro frgments of the injector port sept nd high boiling smple residul deposited in the injection port sleeve or on the inner wll t the front of the cpillry column. The degrdtion of endrin is monitored using the Lbortory Performnce Check Stndrd (Section 9.2). 4.6 Interfering nd errtic peks hve been observed in method blnks within the retention windows of metribuzin, lchlor, cynzine nd heptchlor. These re believed to be due to phthlte contmintion. This contmintion cn be reduced by pying specil ttention to regent preprtion (See solvent rinsing the dry buffer nd the dechlorintion/ preservtive slts, Section ) nd elimintion of ll forms of plstic from the procedure (i.e., HDPE bottles, 5.0 SAFETY plstic weighing bots, etc.). After NCl or N SO is muffled or phosphte 2 4 buffer nd dechlorintion/preservtive slts re solvent rinsed, they should be stored in seled glss continers. NCl, N SO, phosphte buffer, nd 2 4 dechlorintion/preservtive slts should be weighed using glss bekers, never plstic weighing bots. 5.1 The toxicity nd crcinogenicity of chemicls used in this method hve not been precisely defined; ech chemicl should be treted s potentil helth hzrd, nd exposure to these chemicls should be minimized. Ech lbortory is responsible for mintining wreness of OSHA regultions regrding sfe hndling of chemicls used in this method. Additionl references to lbortory sfety re vilble for the informtion of the nlyst. 5.2 The following hve been tenttively clssified s known or suspected humn or mmmlin crcinogens: Chloroform, 1,2-Dibromo-3-Chloropropne, 1,2-Dibromoethne, Heptchlor, nd Hexchlorobenzene

8 5.3 The toxicity of the extrction solvent, MTBE, hs not been well defined. Susceptible individuls my experience dverse ffects upon skin contct or inhltion of vpors. Therefore, protective clothing nd gloves should be used nd MTBE should be used only in chemicl fume hood or glove box. The sme precution pplies to pure stndrd mterils. 6.0 EQUIPMENT AND SUPPLIES (All specifictions in Sections 6.0 nd 7.0 re suggested. Ctlog numbers re included for illustrtion only.) 6.1 Smple Continers ml screw cp glss vils (Kimble #60958A-16, Fisher # E or equivlent) ech equipped with size cp nd PTFE-fced sept (Kimble # , Fisher # A or equivlent). Prior to use or following ech use, wsh vils nd sept with detergent nd tp wter then rinse thoroughly with distilled wter. Allow the vils nd sept to dry t room temperture, plce only the vils in n oven nd het to 400 C for 30 minutes. After removl from the oven llow the vils to cool in n re known to be free of orgnics. After rinsing cps with distilled wter, rinse in beker with HPLC grde or better cetone nd plce in drying oven t 80 C for one hour. 6.2 Vils -- Autosmpler, 2.0 ml vil with screw or crimp cp nd Teflon-fced sept. 6.3 Micro Syringes µl, 25 µl, 50 µl, 100 µl, 250 µl, nd 1000 µl. 6.4 Pipettes ml or 5.0 ml, Type A, TD, glss. 6.5 Volumetric Flsk ml, 100 ml, 250 ml, nd 500 ml glss stoppered. 6.6 Disposble Psteur Pipets, 9 inch -- Used for extrct trnsfer. 6.7 Stndrd Solution Storge (SSS) Continers ml Boston round, mber glss bottles with TFE-lined cps or equivlent. 6.8 Blnce -- Anlyticl, cpble of ccurtely weighing to the nerest g. 6.9 Gs Chromtogrphy System The GC must be cpble of temperture progrmming nd should be equipped with linerized electron cpture detector (ECD), fused silic cpillry column, nd on-column or splitless injector (splitless mode, 30 second dely). If simultneous confirmtion is employed the GC must hve second ECD. An uto-smpler/injector is desirble Specil Precution: During method development, problem ws encountered with the syringe on the utosmpler. The syringe plunger, fter repeted smple extrct injections, developed resistnce when withdrwn or inserted into the

9 syringe brrel. This resistnce ws due to slt deposits in the syringe brrel which were left behind following the evportion of hydrted MTBE. To minimize this problem, unique syringe wsh procedure ws employed. After smple injection, the syringe ws first rinsed three times with regent wter then three times with MTBE. This effectively removed ll the residul slt fter ech injection from the syringe nd surmounted the problem. Some utosmpler designs my not encounter this problem but this precution hs been mentioned to lert the nlyst. When pentne ws used s the extrction solvent, this ws not problem Two GC columns re recommended. Column A is recommended s the primry nlyticl column unless routinely occurring nlytes re not dequtely resolved. Column B is recommended for use s confirmtory column when GC/MS confirmtion is not sensitive enough or unvilble. Other GC columns or conditions my be employed provided dequte nlyte resolution is ttined nd ll the qulity ssurnce criteri estblished in Section 9.0 re met Column A mm ID x 30 m fused silic cpillry with chemiclly bonded methyl polysiloxne phse (J&W, DB-1, 1.0 m film thickness or equivlent). As result of the different boiling points of MTBE (b.p. 55 C) nd pentne (b.p. 35 C), two different GC oven temperture progrms re specified in Tble 1 for MTBE nd Tble 12 for pentne. Retention times for trget nlytes were slightly different using the pentne oven temperture progrm but elution order, nlyte resolution, nd totl nlysis time were not effected. Injector temperture: 200 C equipped with 4 mm ID dectivted sleeve with wool plug (Restek #20781 for HP GC's or equivlent). This sleeve design ws found to give better nlyte response thn the stndrd 2 mm sleeve. Detector temperture: 290 C Column B mm ID x 30 m with chemiclly bonded 6% cynopropylphenyl/94% dimethyl polysiloxne phse (Restek, Rtx-1301, 1.0 µm film thickness or equivlent). The column oven ws temperture progrmmed exctly s indicted for column A (Tbles 1 nd 12). Injector nd detector tempertures t 200 C nd 290 C, respectively. The sme temperture progrm ws utilized to llow for simultneous confirmtion nlysis To perform simultneous confirmtion from single injection onto both the primry nd confirmtion columns, two injector setups cn be employed

10 Using two hole grphite ferrule (Restek #20235, or equivlent) both columns cn be inserted into one injection port. To ensure the column ends re centered in the injection port sleeve nd not ngled to the side, n inlet dptor fitting is instlled t the bse of the injection port (Restek #20633, or equivlent). Use cution when instlling columns in this mnner to ensure the column does not brek t the bse of the injector due to the two columns twisting s the ferrule nut is tightened. To minimize this hzrd, the ferrule nut cn be reverse twisted four to five times once the ferrule hs been seted An lternte procedure involves instlling 1 mr portion of 0.25 mm dectivted, uncoted fused silic cpillry tubing (Restek #10043, or equivlent) into the injector s norml single column is instlled. Then using Y-press tight union (Restek #20403 or equivlent) join the 1 m uncoted column to the primry nd secondry columns. Using this procedure will reduce detection limits when compred to the procedure outline in Section since only one column is positioned in the injection port to receive the injected smple extrct The nlyst is permitted to modify GC columns, GC conditions, internl stndrd or surrogte compounds. Ech time such method modifictions re mde, the nlyst must repet the procedures in Section REAGENTS AND STANDARDS 7.1 Regents MTBE -- High purity grde. It my be necessry to double distill the solvent if impurities re observed which coelute with some of the more voltile compounds Pentne (Optionl Extrction Solvent), High Purity Grde -- It my be necessry to double distill the solvent if impurities re observed which coelute with some of the more voltile compounds Acetone, High Purity -- Demonstrted to be free of nlytes Methnol, High Purity -- Demonstrted to be free of nlytes Sodium Chloride, NCl, ACS Regent Grde -- Before using btch of NCl, plce in muffle furnce, increse temperture to 400 C nd hold for 30 minutes. Store in cpped glss bottle, not in plstic continer

11 7.1.6 Sodium Sulfte, N2SO 4, ACS Regent Grde -- Before using btch of N2SO 4, plce in muffle furnce, increse temperture to 400 C nd hold for 30 minutes. Store in cpped glss bottle not in plstic continer Smple Preservtion Regents Phosphte Buffer -- Used to lower the smple mtrix ph to 4.8 to 5.5 in order to inhibit bse ctlyzed degrdtion of the 7 hlocetonitriles, some of the chlorinted solvents, nd to stndrdize the ph of ll smples. Prepre dry homogeneous mixture of 1% Sodium Phosphte, dibsic (N2HPO 4)/99% Potssium Phosphte, monobsic (KH PO ) by weight (exmple: g N HPO nd 198 g KH PO to yield totl weight of 200 g) Both of these buffer slts should be in grnulr form nd of ACS grde or better. Powder would be idel but would require extended clenup time s outlined below in Section to llow for buffer/solvent settling Ammonium Chloride, NH Cl, ACS Regent Grde -- Used to 4 convert free chlorine to monochlormine. Although this is not the trditionl dechlorintion mechnism, mmonium chloride is ctegorized s dechlorinting gent in this method Sodium Sulfite, N SO, ACS Regent Grde -- Used s 2 3 dechlorinting gent for chlorl hydrte smple nlysis To simplify the ddition of 6 mg of the dechlorinting gent to the 60 ml vil, the dechlorinting slt is combined with the phosphte buffer s homogeneous mixture. Add 1.2 g of the pproprite dechlorinting gent to 200 g of the phosphte buffer. When 1 g of the buffer/dechlorinting gent mixture re dded to the 60 ml smple vil, 6 mg of the dechlorinting gent re included reflecting n ctul concentrtion of 100 mg/l. Two seprte mixtures re prepred, one contining mmonium chloride nd the other with sodium sulfite If bckground contminnts re detected in the slts listed in Sections through , solvent rinse clenup procedure my be required. These contminnts my coelute with some of the high moleculr weight herbicides nd pesticides. These slts cnnot be muffled since they decompose when heted to 400 C. This solvent rinsing procedure is pplied to the homogeneous mixture prepred in Section

12 Note: If lbortory is not conducting nlyses for the high moleculr weight herbicides nd pesticides, this clenup my not be required if no interfering peks re observed within the retention time window (Section 12.2) for ny trget nlytes in the lbortory regent blnk. SOLVENT RINSE CLEANUP PROCEDURE Prepre two seprte homogeneous mixtures of the phosphte buffer slts (Section ) in 500 ml beker. To one, dd the correct mount of mmonium chloride nd to the other dd the correct mount of sodium sulfite. Three seprte solvents re then used to rinse the mixture. (This solvent rinsing must be performed in fume hood or glove box.) First, dd pprox. 100 ml of methnol, or enough to cover the slt to depth of pprox. 1 cm, nd using clen sptul, stir the solvent slt mixture for one minute. Allow the buffer/solvent mixture to settle for one minute nd then decnt the methnol, being creful not to pour off the rinsed buffer. It my be necessry to perform this procedure up to four times with methnol. Note: By softly lifting nd tpping the bse of the beker ginst the fume hood counter surfce, more of the solvent is brought to the surfce of the buffer. Next, perform the identicl procedure up to two times using cetone. Finlly, perform two finl rinses with the pproprite extrcting solvent (MTBE or Pentne). After the finl solvent rinse, plce the "wet" buffer on hot plte t pprox. 60 C for 30 minutes or until dry. Stir the mixture every five minutes to id the evportion of excess solvent. Once dry, plce the buffer in glss bottle with either ground glss stopper or TFE-fced septum. 7.2 Regent Wter -- Regent wter is defined s purified wter which does not contin ny mesurble quntities of ny trget nlytes or ny other interfering species A Millipore Super-Q wter system or its equivlent my be used to generte deionized regent wter. Distilled wter tht hs been chrcol filtered my lso be suitble Test regent wter ech dy it is used by nlyzing ccording to Section

13 7.3 Stock Stndrd Solutions (SSS) -- These solutions my be obtined s certified solutions or prepred from net mterils using the following procedures: For nlytes which re solids in their pure form, prepre stock stndrd solutions (1 mg/ml) by ccurtely weighing pproximtely 0.01 g of pure mteril in 10 ml volumetric flsk. Dilute to volume with cetone. Due to the low solubility of simzine, this stock should be prepred t 0.5 mg/ml by weighing g diluted to volume with cetone in 10 ml volumetric flsk. Alterntively, simzine stock stndrd solutions my be prepred in ethyl cette t pproximtely 0.01 g/10 ml. Stock stndrd solutions for nlytes which re liquid in their pure form t room temperture cn be ccurtely prepred in the following mnner Plce bout 9.8 ml of cetone into 10 ml ground-glss stoppered volumetric flsk. Allow the flsk to stnd, unstoppered, for bout 10 minutes to llow solvent film to evporte from the inner wlls of the volumetric flsk, nd weigh to the nerest 0.1 mg Use 10 µl syringe nd immeditely dd 10.0 µl of stndrd mteril to the flsk by keeping the syringe needle just bove the surfce of the cetone. Cution should be observed to be sure tht the stndrd mteril flls dropwise directly into the cetone without contcting the inner wll of the volumetric flsk Reweigh, dilute to volume, stopper, then mix by inverting the flsk severl times. Clculte the concentrtion in milligrms per milliliter from the net gin in weight. Finl concentrtion should be between mg/ml Lrger volumes of stndrd solution my be prepred t the discretion of the nlyst. When compound purity is ssyed to be 96% or greter, the weight cn be used without correction to clculte the concentrtion of the stock stndrd Commercilly prepred stock stndrds cn be used t ny concentrtion if they re certified by the mnufcturer or by n independent source. When purchsing commercilly prepred stock stndrds, every effort should be mde to void solutions prepred in methnol (chlorl hydrte is n exception, Section ). Methnol cn cuse degrdtion of most of the hlocetonitriles. In ddition, some commercil suppliers hve reported instbility with solutions of 18 simzine nd trzine prepred in methnol. For these resons, cetone should be used s the primry solvent for stock stndrd nd primry dilution stndrd preprtion nd ll sources of methnol introduction into these cetone solutions should be eliminted

14 It is extremely difficult to cquire chlorl hydrte in its pure form since it is clssified s controlled substnce. Consequently, if pure chlorl hydrte cnnot be cquired, commercilly prepred solution of this nlyte (most often t 1.0 mg/ml) must be purchsed. Most mnufctures provide certified chlorl hydrte solutions in methnol. Since chlorl hydrte is unstble, stndrds from seprte vendor must be utilized to confirm the ccurcy of the primry supplier's solution Outside source stock solutions, which re independently prepred or purchsed from n outside source different from the source for the originl stock stndrd solutions, must be used s mens of verifying the ccurcy of the originl stock stndrd solutions for ll nlytes. Prepre dilution of both stocks in cetone nd perform finl dilution in MTBE such tht ech stock dilution is t the sme concentrtion. Anlyze s outlined in Section The reltive percent difference (RPD s defined below) between the nlytes' response (re counts) from both solutions should not exceed 25% for ny one nlyte. The RPD must be less thn 20% for 90% or greter of the totl number of trget nlytes nlyzed If this criteri cnnot be met, third outside source should be purchsed nd tested in the sme mnner. When two sources of stock solutions gree, the ccurcy of the stock solutions is confirmed. This should be done prior to prepring the primry dilution stndrds Stock Solution of Surrogte -- Prepre stock solution of the surrogte stndrd in cetone by weighing pprox g decfluorobiphenyl in 10 ml volumetric flsk. When diluted to volume this yields concentrtion of 1.00 mg/ml. Alternte surrogte nlytes my be selected provided they re similr in nlyticl behvior to the compounds of interest, re highly unlikely to be found in ny smple, nd do not coelute with trget nlytes Stock Solution of Internl Stndrd (IS) -- Use of n IS is optionl when MTBE is the extrction solvent but mndtory if pentne is used. This is due to the high voltility of pentne when compred to MTBE (see boiling points, SectION ). Prepre n internl stndrd stock solution of bromofluorobenzene (BFB) in cetone. Since this compound is liquid t room temperture, the procedure outlined in Sections through should be followed but dd pproximtely 65 µl of net BFB rther thn 10 µl s specified in

15 Section When diluted to volume this yields concentrtion ner 10.0 mg/ml. Alternte internl stndrd nlytes my be selected provided they re highly unlikely to be found in ny smple nd do not coelute with trget nlytes Trnsfer the stock stndrd solutions into Teflon-lined screw cp mber bottles. Store t 4 C or less nd protect from light. Stock stndrd solutions should be checked frequently for signs of degrdtion or evportion, especilly just prior to prepring clibrtion stndrds from them When stored in freezer t <-10 C, the THM stock stndrds hve been shown to be stble for up to six months. The other nlyte stock stndrds, with the exception of chlorl hydrte, hve been shown to be stble for t lest four months when stored in freezer (<-10 C). Chlorl hydrte stock stndrds, when stored in freezer (<-10 C), hve been shown to be stble for two months, however, since freezers cn hold t vrious tempertures below -10 C, fresh chlorl hydrte stndrds should be initilly prepred weekly, until the stbility of this nlyte is determined for specific lbortory setting. 7.4 Primry Dilution Stndrds (PDS) -- Two seprte groups of primry dilution stndrds must be prepred; one set in cetone for ll the method nlytes except chlorl hydrte nd the second set in methnol for chlorl hydrte. Although preprtion of seprte chlorl hydrte stndrds my seem lborious, due to the stbility problems encountered with this nlyte, mking fresh chlorl hydrte primry dilution stndrds is more efficient. Prepre primry dilution stndrds by combining nd diluting stock stndrds in cetone (methnol for chlorl hydrte). The primry dilution stndrds should be prepred such tht when 25 µl of this primry dilution stndrd re dded to 50 ml of buffered/dechlorinted regent wter (Section ), queous concentrtions will brcket the working concentrtion rnge. Store the primry dilution stndrd solutions in vils or bottles, with cps using TFE fced liners, in freezer (<-10 C) with miniml hedspce nd check frequently for signs of deteriortion or evportion, especilly just before prepring clibrtion stndrds. The sme comments on storge stbility in Section pply to primry dilution stndrds Surrogte Primry Dilution Stndrd -- Dilute 500 µl of the surrogte stock solution to volume with cetone in 50 ml volumetric flsk. This yields primry dilution stndrd t 10.0 µg/ml. Addition of 50 µl of this stndrd to 50 ml of queous smple yields finl concentrtion in wter of 10.0 µg/l. This solution is fortified into the queous smple prior to extrction of ll clibrtion stndrds (Section ), qulity control smples (Section 9.0), LRBs (Section 9.3.1) nd ctul field smples (Section ) in the extrction set

16 7.4.2 Internl Stndrd (IS) Primry Dilution Stndrd -- Prepre IS primry dilution stndrd t 100 µg/ml by diluting the pproprite mount of internl stndrd stock solution (500 µl if stock is 10.0 mg/ml) to volume with cetone in 50 ml volumetric flsk. When 10 µl of this solution re dded to 1.0 ml of extrct, the resultnt finl concentrtion is 1.00 µg/ml. The internl stndrd is used in order to perform n internl stndrd clibrtion nd is dded to n nlyticlly precise volume of the extrct following extrction. This solution is dded to ll extrcts Reserve pproximtely 10 ml liquot of the sme lot of both the cetone nd methnol used in the preprtion of the primry dilution stndrds. When vlidting the ccurcy of the clibrtion stndrds (Section 7.3.4), fortify lbortory regent blnk with 25 µl of both the cetone nd the methnol which ws used to prepre the primry dilution stndrds. Anlysis of this lbortory regent blnk will confirm no trget nlyte contmintion in the solvents used to prepre the primry dilution stndrds. 7.5 Lbortory Performnce Check Solution (LPC) -- To insure proper instrument performnce, Lbortory Performnce Check Solution is prepred. This solution is prepred in MTBE for direct injection on the GC nd is used to evlute the prmeters of instrument sensitivity, chromtogrphic performnce, column performnce nd nlyte brekdown. These prmeters re listed in Tble 7 long with the method nlytes utilized to perform this evlution, their concentrtion in MTBE nd the cceptnce criteri. To prepre this solution t the concentrtions listed in Tble 7, double dilution of the nlyte stock solutions must be mde. First prepre primry stock dilution mix t 1000 times the concentrtions listed in Tble 7, by dding the pproprite volume of ech stock solution to single 50 ml volumetric flsk contining pproximtely 25 ml of MTBE. Dilute to volume with MTBE. Then the LPC working solution is prepred in MTBE by diluting 50 µl of the primry stock dilution mix in MTBE to 50 ml in volumetric flsk. The best wy to ccomplish this is to dd pproximtely 48 ml MTBE to the 50 ml volumetric flsk nd dd 50 µl of the primry stock dilution mix, then dilute to volume with MTBE. Store this solution in vil or bottle, with TFE fced cp, in freezer (<-10 C) with miniml hedspce nd check frequently for signs of deteriortion or evportion If lbortory is not conducting nlyses for the high moleculr weight pesticides nd herbicides, modified LPC my be prepred. This modified LPC cn omit the endrin nlyte brekdown component s well s the resolution requirement for bromcil nd lchlor under column performnce. In ddition, substitute nlytes in plce of lindne for the sensitivity check nd hexchlorocyclopentdiene for chromtogrphic performnce cn be selected. These substitute compounds must meet the sme criteri s listed in Tble 7 with the concentrtion for sensitivity check ner the substitute nlyte's EDL nd the concentrtion for chromtogrphic performnce ner 50 times the

17 substitute nlyte's EDL. The column performnce criteri for resolution between bromodichloromethne nd trichloroethylene cnnot be modified If pentne is selected s n lternte extrction solvent the LPC must lso be prepred in pentne. 8.0 SAMPLE COLLECTION, PRESERVATION, AND STORAGE 8.1 Smple Vil Preprtion To conduct nlyses for the totl nlyte list, two sets of 60 ml vils must be prepred for smpling. One set of vils, prepred for the nlysis of ll trget nlytes except chlorl hydrte, contins mmonium chloride s dechlorinting gent. Due to concerns over low recoveries for chlorl hydrte in mtrices preserved with mmonium chloride (Section 8.1.2), seprte smple set must be collected nd preserved with sodium sulfite. Both sets of vils re prepred s follows Using the homogeneous phosphte buffer/dechlorinting gent mixtures prepred in Section , 1 g of the pproprite mixture re dded to the corresponding vils If the smple ssy is for only the THMs nd/or solvents, either dechlorinting gent cn be dded. However, sodium sulfite promotes the decomposition of the hlocetonitriles, 1,1-dichloro-2-propnone, 1,1,1-trichloro-2-propnone nd chloropicrin nd therefore mmonium chloride must be used s the dechlorintion regent in their nlysis. In ddition, some fortified mtrices, dechlorinted with mmonium chloride, hve displyed recoveries of chlorl hydrte which hve been up to 50% lower thn expected, when compred to the sme smple mtrix dechlorinted with sodium sulfite. In other mtrices, recoveries hve been consistent regrdless of dechlorinting gent. The reson for these differences hs not been determined. Due to this uncertinty, seprte smple, dechlorinted with 100 mg/l sodium sulfite must be collected for the nlysis of chlorl hydrte The dechlorinting gents, if not dded within the homogeneous mixture of the buffer, must be dded to the smpling vils s dry slt. Solutions of the dechlorinting gents should not be used due to concerns over the stbility of these slts dissolved in solution nd the potentil chemicl interctions of queous solutions of these slts with the dry phosphte buffer Smples must contin either 100 mg/l mmonium chloride or sodium sulfite, s pproprite for the nlysis being performed. This mount will eliminte free chlorine residul in typicl chlorinted drinking

18 8.2 Smple Collection wter smples. If high chlorine doses re used, such s in mximum formtion potentil test, dditionl dechlorinting regent my be required Collect ll smples in duplicte. Fill smple bottles to just overflowing but tke cre not to flush out the buffer/dechlorintion regents. No ir bubbles should pss through the smple s the bottle is filled, or be trpped in the smple when the bottle is seled When smpling from wter tp, open the tp nd llow the system to flush until the wter temperture hs stbilized (usully bout three to five minutes). Remove the ertor nd djust the flow so tht no ir bubbles re visully detected in the flowing strem When smpling from n open body of wter, fill 1 q wide-mouth glss bottle or 1 L beker with smple from representtive re, nd crefully fill duplicte 60 ml smple vils from the continer The smples must be chilled to 4 C on the dy of collection nd mintined t tht temperture until nlysis. Field smples tht will not be received t the lbortory on the dy of collection must be pckged for shipment with sufficient ice to ensure they will be t 4 C on rrivl t the lbortory. Synthetic ice (i.e., Blue ice) is not recommended. 8.3 Smple Storge/Holding Times Store smples t 4 C nd extrcts in freezer (<-10 C) until nlysis. The smple storge re must be free of orgnic solvent vpors Extrct ll smples within 14 dys of collection nd nlyze within 14 dys following extrction. This pplies to either MTBE or pentne extrcts). Smples not nlyzed within these time periods must be discrded nd replced. 9.0 QUALITY CONTROL 9.1 Ech lbortory tht uses this method is required to operte forml qulity control (QC) progrm. Minimum QC requirements include the lbortory performnce check stndrd, initil demonstrtion of lbortory cpbility, method detection limit determintion, nlysis of lbortory regent blnks, continuing clibrtion check stndrd, lbortory fortified smple mtrices, field duplictes nd monitoring surrogte nd/or internl stndrd pek response in ech smple nd blnk. Additionl qulity control prctices my be dded

19 9.2 Assessing Instrument System -- Lbortory Performnce Check Stndrd (LPC) -- Prior to ny smple nlyses, lbortory performnce check stndrd must be nlyzed. The LPC smple contins compounds designed to indicte pproprite instrument sensitivity, endrin brekdown, column performnce (primry column), nd chromtogrphic performnce. LPC smple components nd performnce criteri re listed in Tble 7. Inbility to demonstrte cceptble instrument performnce indictes the need for reevlution of the instrument system. The sensitivity requirement is bsed on the Estimted Detection Limits (EDLs) published in this method. If lbortory EDLs differ from those listed in this method, concentrtions of the LPC stndrd must be djusted to be comptible with the lbortory EDLs. If endrin brekdown exceeds 20%, the problem cn most likely be solved by performing routine mintennce on the injection port including replcing the injection port sleeve, nd ll ssocited sels nd sept. If column or chromtogrphic performnce criteri cnnot be met, new columns my need to be instlled, column flows corrected, or modifictions dpted to the oven temperture progrm. During erly method development work, significnt chromtogrphic nd column performnce problems were observed while using DB-1 column which hd been used for severl yers for drinking wter extrct nlysis. By instlling new DB-1 column, these performnce problems were overcome. If the columns to be used for this method hve been used for severl yers or hve hd extended use with extrcts from hrsh smple mtrices (i.e., wstewter, cidified smple extrcts, hzrdous wste smples) it my be difficult to meet the criteri estblished for this LPC stndrd nd column replcement my be the best lterntive. 9.3 Lbortory Regent Blnks (LRB) -- Before processing ny smples, the nlyst must nlyze n LRB to demonstrte tht ll glsswre nd regent interferences re under control. In ddition, ech time set of smples is extrcted or regents re chnged, LRB must be nlyzed. If the LRB produces pek within the retention time window of ny nlyte (Section 12.2) preventing the quntittion of tht nlyte, determine the source of the contmintion nd eliminte the interference before processing smples. LRB smples must contin the pproprite buffer for the trget nlytes (buffered/nh4cl dechlorinted nd/or buffered/n2so 3 dechlorinted regent wter) Prepre the two LRBs in the pproprite buffered/dechlorinted regent wter. Add 50 µl of surrogte primry dilution stndrd (Section 7.4.1) to ech blnk nd follow the procedure outlined in Section Initil Demonstrtion of Cpbility (IDC) Preprtion of the IDC Lbortory Fortified Blnk (LFB) -- Select concentrtion for ech of the trget nlyte which is pproximtely 50 times the EDL or close to the expected levels observed in field smples. Concentrtions ner nlyte levels in Tble 3.A re

20 recommended. Prepre LFB by dding the pproprite concentrtion of the primry dilution stndrd (Section 7.4) to ech of four to seven 50 ml liquots of buffered/nh Cl dechlorinted regent wter. 4 Seprte N SO preserved mtrices need not be nlyzed 2 3 (Section ). Anlyze the liquots ccording to the method beginning in Section Chlorl hydrte is included in the buffered/nh Cl 4 dechlorinted regent wter, contining ll the other trget nlytes since no mtrix induced recovery problems hve been found from regent wter preserved with NH Cl Following procedurl clibrtion stndrd nlysis nd subsequent instrument clibrtion, nlyze set of t lest seven IDC smples nd clculte the men percent recovery (R) nd the reltive stndrd devition of this recovery (RSD). The percent recovery is determined s the rtio of the mesured concentrtion to the ctul fortified concentrtion. For ech nlyte, the men recovery vlue must fll within the rnge of % nd the RSD must not exceed 15%. For those compounds tht meet these criteri, performnce is considered cceptble, nd smple nlysis my begin. For those compounds tht fil these criteri, this procedure must be repeted using eight fresh smples until stisfctory performnce hs been demonstrted The initil demonstrtion of cpbility is used primrily to preclude lbortory from nlyzing nd reporting unknown smples without obtining some experience with n unfmilir method. It is expected tht s lbortory personnel gin experience with this method, the qulity of dt will improve beyond those specified in Section Method Detection Limits (MDL) -- Prior to the nlysis of ny field smples the method detection limits must be determined. Initilly, estimte the concentrtion of n nlyte which would yield pek equl to five times the bseline noise nd drift. Prepre primry dilution stndrd with nlyte concentrtions t 1000 times this level in cetone (or methnol for chlorl hydrte) Prepre 500 ml liquot of buffered/mmonium chloride dechlorinted regent wter. Fill minimum of seven replicte, 60 ml vils with 50 ml of the buffered/dechlorinted (NH4Cl) regent wter Fortify the 50 ml buffered/dechlorinted (NH4Cl) regent wter with 50 µl of both the MDL concentrte prepred in cetone nd the chlorl hydrte MDL concentrte in methnol. Seprte preprtion of regent wter contining N2SO 3 s the dechlorinting gent for chlorl hydrte MDL determintion is not necessry. (See Section )

21 Extrct nd nlyze these smples s outlined in Section MDL determintion cn then be performed s discussed in Section Lbortory Fortified Blnk (LFB) -- Since this method utilizes procedurl clibrtion stndrds, which re fortified regent wter, there is no difference between the LFB nd the continuing clibrtion check stndrd. Consequently, there is not requirement for the nlysis of n LFB. However, the criteri estblished for the continuing clibrtion check stndrd (Section 10.4) should be evluted s the LFB. 9.6 Lbortory Fortified Smple Mtrix (LFM) -- The lbortory must dd known concentrtions of nlytes to minimum of 10% of the routine smples or one fortified smple per smple set, whichever is greter, for both NH Cl nd 4 N SO dechlorinted smple mtrices. The concentrtions should be equl to 2 3 or greter thn the bckground concentrtions in the smple selected for fortifiction. Over time, smples from ll routine smple sources should be fortified. By fortifying smple mtrices nd clculting nlyte recoveries, ny mtrix induced nlyte bis is evluted. When n nlyte recovery flls outside the cceptnce criteri outlined below, bis is concluded nd tht nlyte for tht mtrix is reported to the dt user s suspect First, follow the procedure outlined in Section Next, prepre the LFM by dding 50 µl of n cetone bsed stndrd solution into the remining 50 ml of the buffered/nh4cl dechlorinted smple mtrix in the vil in which it ws smpled. This smple vil will hve hd the required mount of queous smple removed s specified in Section Add 50 µl of surrogte primry dilution stndrd (Section 7.4.1) nd follow procedure outlined in Sections 11.0 nd When chlorl hydrte is being determined, prepre the LFM by dding 50 µl of methnol bsed chlorl hydrte stndrd solution into 50 ml of the buffered/n2so 3dechlorinted smple mtrix in the vil in which it ws smpled. Add 50 µl of surrogte primry dilution stndrd (Section 7.4.1) nd follow procedure outlined in Sections 11.0 nd Clculte the percent recovery, R, of the concentrtion for ech nlyte, fter correcting the totl mesured concentrtion, A, from the fortified smple for the bckground concentrtion, B, mesured in the unfortified smple, i.e.: where: C = the fortifying concentrtion

22 The recoveries of ll nlytes being determined must fll between 75% nd 125% nd the recoveries of t lest 90% of these nlytes must fll between 80% nd 120%. This criteri is pplicble to both externl nd internl stndrd clibrted quntittion If recovery flls outside of this cceptble rnge, mtrix induced bis cn be ssumed for the respective nlyte nd the dt for tht nlyte in tht smple mtrix must be reported to the dt user s suspect If the unfortified mtrix hs nlyte concentrtions equl to or greter thn the concentrtion fortified, duplicte smple vil needs to be fortified t higher concentrtion. If no such smple is vilble the recovery dt for the LFM smple should not be reported for this nlyte to the dt user. 9.7 Field Duplictes (FD1 nd FD2) -- The lbortory must nlyze field smple duplicte for minimum of 10% of the totl number of field smples or t lest one field smple duplicte per smple set, whichever is greter. Duplicte results must not reflect reltive percent difference (RPD s defined below) greter thn 25% for ny one nlyte nd the RPD for 90% of the nlytes being determined must be less thn 20%. where: FD1 nd FD2 = the quntified concentrtion on n individul nlyte for the initil nd duplicte field smple nlysis, respectively If this criteri is not met the nlysis must be repeted. Upon repeted filure, the smpling must be repeted or the nlyte out of control must be reported s suspect to the dt user. 9.8 Assessing Surrogte Recovery The surrogte nlyte is fortified into the queous portion of ll clibrtion stndrds, qulity control smples nd field smples. By monitoring the surrogte response, the nlyst genertes useful qulity control informtion from extrction precision through quntittive nlysis. Devitions in surrogte recovery my indicte n extrction problem. If using externl stndrd clibrtion the surrogte retention time functions s reference for identifiction of trget nlytes Using the men surrogte response from the clibrtion stndrd nlyses (Cl SR), determine the surrogte percent recovery (%REC S ) in ll clibrtion stndrds, LFBs, nd LFMs, nd field smples. This

23 recovery is clculted by dividing the surrogte response from the smple (Sm SR) by the men response from the initil clibrtion stndrds (Section 10.2 or Section 10.3) nd multiplying by 100, s shown below. Recoveries must fll within the rnge of %. If smple provides recovery outside of this rnge, the extrct must be renlyzed. If upon renlysis, the recovery continues to fll outside the cceptble rnge fresh smple should be extrcted nd nlyzed. If this is not possible the dt for ll the nlytes from this smple should be reported to the dt user s suspect due to surrogte recovery outside cceptble limits If consecutive smples fil the surrogte response cceptnce criterion, immeditely nlyze continuing clibrtion stndrd If the continuing clibrtion stndrd provides recovery within the cceptble rnge of %, then follow procedures itemized in Section for ech smple filing the surrogte response criterion If the check stndrd provides surrogte recovery which flls outside the cceptble rnge or fils the cceptnce criteri specified in Section 10.4 for the trget nlytes, then the nlyst must reclibrte, s specified in Section Assessing the Internl Stndrd (IS) When using the internl stndrd clibrtion procedure, the nlyst must monitor the internl stndrd response (pek re or pek height) of ll smples during ech nlysis dy. The internl stndrd response should not devite from men internl stndrd response of the pst five continuing clibrtion stndrds by >20% If >20% devition occurs with n individul extrct, optimize instrument performnce nd inject second liquot of tht extrct If the reinjected liquot produces n cceptble internl stndrd response, report results for tht liquot If devition of >20% is obtined for the reinjected extrct, nlysis of clibrtion check stndrd must be performed (Section 10.4)