Certification of a reference materialfor herbicides in water by way ofinter laboratory comparison B. Lalrea, V. Le Diourona, M. Dsenfanta,K. El Mrabeta,b V. Pichonb, J. Vialb, G. Hervoetaa Laboratoire National de Mtrologie et dEssais (LNE), 1 rue Gaston Boissier,75724 Paris cedex 15, France b Laboratoire Environnement et Chimie Analytique (LECA) UMR-CNRS 7121, Ecole Suprieure de Physique et Chimie Industrielles, 10 rue Vauquelin,75231 Paris Cedex 05, France ABSTRACT:Thecertifiedreferencematerials(CRMs)areamongthemostappropriatetoolsforthe traceabilityandvalidationofanalyticalmethods.Althoughtheirnumberseemstobehigh20,000,they onlycoverasmallpartoftheanalyticalneedsforenvironmentalmonitoring.Untilnow,nonewere available for analyzing pesticides in water. Afteranintralaboratoryfeasibilitystudyandanevaluationofthebehaviorofthismaterialduring interlaboratorytesting,theLNEhasproducedandcertifiedaCRMforthetriazineandphenylurea analysis in water samples. Introduction InaccordancewiththeEuropeanoutlinedirectiveonwater(DCE),the departmentofecologypublishedmemorandumserviceinstructionDCE2006/16 relatingtotheconstitutionandimplementationofamonitoringprogramforthe differentwatercategories.Becauseofthis,qualityofriversandgroundwateris regularlymonitored.Pesticidecontent,amicropollutantconsideredasa priority by the European Union in particular is verified.In order to achieve this monitoring, several measures are taken daily by different laboratories. It is important to be able to compare results. This objective can only be reachedbyensuringtraceabilityoftheseanalyseswiththehelpofdifferenttools suchascertifiedreferencematerial(CRM),thelinktonationalstandardsthrough uninterruptedchainsofcomparisonandaparticipationininterlaboratorytesting. CRMs have the advantage of also being able to evaluate accuracy during validation ofanalyticalmethodsimplemented.Theycanbeoftwotypes:thosedestinedto calibratemeasurementsystemsandmatricesmakingitpossibletoconsiderall steps from the preparation of the sample. 4 Transverse Disciplines in Metrology Untilnow,therewerenonefortheanalysisofpesticidesinwater.Thatiswhy LNEincooperationwithLECAdecidedtodevelopone.Thisprojectstartedfour yearsagowithafeasibilitystudyofsuchamaterial.Thebehaviorofproducts developed was then evaluated during an interlaboratory comparison. A group of CRMs was developed in March 2006 and certified in June 2006 for the analysis of triazines and phenylureas in drinking water. Previous studies: feasibility and behavior of RM The following components which belong to two pesticide families were selected: triazines:deisopropylatrazine(DIA),deethylatrazine(DEA),simazine,atrazine, terbutylazine and terbutryne. phenylureas: chlortoluron, diuron, isoproturon and linuron. Completedin2002,thischoice,exceptforterbutylazineandDIA,isbasedon thefrequencyofdetectionofthesetriazinesandphenylureasinwater[1].In addition,theyareindexedinthelistof50pesticidessoldinlargerquantitiesthan 500 tons per year in Europe. Terbutylazine, following the ban on the use of atrazine, ispartofthemixusedforitsreplacementincornculturesandthuswasadded. Despite its usage ban, atrazine can still be detected in water; because of this, two of its metabolites, DEA and DIA were included in this study. Feasibility study Inordertoachievethemostcompletekitpossible,twotypesofreference materials (RM) were retained: sealed vials: targeted pesticides are stored:-in a solution of acetonitrile, -dried after evaporation of the solvent used for their preparation. solidphaseextraction(SPE)cartridgescalledcartridgesinthisdocument:a water sample spiked with each compound is percolated on the support in order to retainthemwithothermoleculesinthesample.Twopolymericsupportswere evaluated:adivinylbenzenecopolymerfunctionalizedwithN-vinylpyrrolidone (OasisHLB,Waters)groupsandapolystyrenedivinylbenzenecopolymer (ENVI Chrom P, Supelco). Analysis laboratories will then have to carry out the elution of compounds.Thesematerialswerepreparedwithtwolevelsofconcentration,targetedin relationtoregulation(0.15g/lfordrinkingwaterand0.50g/linsurfacewater) Chemistry Statistics /Gas Analysis 5 and they are stored under different temperature conditions: Tambiant, T=0.5C and T=-18Cforayear.Everymonth,theevolutionofcompoundconcentrationwas studied by the analysis of vial and cartridge contents. Thedetailedpresentationofresultsforeachcompound,eachtypeofmaterial andeachstorageconditionwasthesubjectofpublication[2].Betweenthe beginning and ending of the study, the evolution was quantified in percentage of the quantityfoundinrelationtotheoneinitiallyintroduced(rateofrecovery).To summarize, compounds are classified into three families of behaviors: non-usablefamily(Figure1):eitherthecompoundsweretotallydegradedor their recovery level after nine months of study are lower than 10%;family with trend (Figure 2): compound concentration evolves over time; familywithouttrend(Figure3):pesticideconcentrationdoesnotevolve significantly over time.Linuron0204060801001200 1 2 3 4 5 6 7 8 9Time (months)Recovery rate (%)Figure 1. Non-usable family example: Linuron stored in vial after dry evaporationand conservation at ambient temperature DIA0204060801001200 1 2 3 4 5 6 7 8 9Time (months)Recovery rate (%)Figure 2. Family with trend example DIA stored in vial after dry evaporationand conservation at ambient temperature 6 Transverse Disciplines in Metrology Atrazine0204060801001200 1 2 3 4 5 6 7 8 9Ti me (months)Recovery rate (%)Figure 3. Family without trend example Atrazine stored in vial after dry evaporationand conservation at T=-18C The results have shown that compounds are stable when then are in a solution of acetonitrilewhentemperaturebecomesambient,whereasitisnecessarytostore themat-20Cwhentheyaredriedinavial.Whentheyarefixedoncartridges, storagetemperaturemustbelowerthan0.5C.Observedbehaviorsareidentical regardless of the level of concentration. The retained RM was then a kit with: vials containing pesticides in acetonitrile; cartridges(OasisHLB,Waters)treatedbypercolationofdrinkingwater containing selected pesticides. As a precaution, they will be stored at -20C. RM behavior during an interlaboratory comparison InordertotesttheconditionsofRMusage(sendingconditions,receptionand analysiswithdifferentmethods),aninterlaboratorytestinvolvingabout15 participants was organized [3]. The variation factors of both components of the material tested vary between 14 and 30% depending on compounds, which is very satisfactory for a circuit involving laboratories using different methods compared to other campaigns [4,5]. Inviewoftheresults(feasibilityandinterlaboratorytest),acertification campaign was then completed. Chemistry Statistics /Gas Analysis 7 Material production and certification This reference material, in the form of a kit is made up of: twovialscontainingapproximately1.2mlofaherbicidessolution(atrazine, deethylatrazine,deisopropylatrazine,simazine,terbutryne,terbutylazine, chlortoluron,linuron,diuron,andisoproturon)inacetonitrile(concentrationfor each pesticide0.1 mg/l); threecartridgesonwhich250mlofadrinkingwaterspikedwithasolutionof herbicidesinacetonitrilewaspercolated,inordertoreachaconcentrationof approximately 0.50 g/l of each compound in water.This material is destined to calibrate the measurement devices and/or to validate the analytical methods for the determination of herbicides in water. Preparation of materials Thepreparationofmaterialsrequiredthecreationofmulticompoundsolutions by consecutive dilutions of a mother solution obtained with pure compounds. Afterpreparation,thesolutionistransferredintovialswhichareimmediately sealed under nitrogen. Forthecartridges,180loftapwaterweretakenthesameday.Before transferring to a cartridge according to the protocol described below, 5 l of water are spiked with 5 ml of a pesticide solution. Cartridges are first conditioned with 3 ml of acetonitrile, 3 ml of methanol, 3 ml of water then 250 ml of spiked water are percolated. Water rinsing and nitrogen flow dryingstepsarethenrealizedbeforestoringtheminspecificconditions(protected fromlightandatatemperaturelowerthan20C).Allthesestepswereconducted with the ASPEC XL IV robot (GILSON). Therewasapriorverificationthatvialsealswouldnotalterthesolutioninside andthatthereliabilityoftherobotwassufficienttoguaranteegoodcartridge homogenity. Vial and cartridge preparations required three days and three weeks respectively. 400 sealed vials and 600 cartridges were produced.8 Transverse Disciplines in Metrology Homogenity The homogenity was verified on two series of ten vials and ten cartridges (Table 1). Table 1. Vial and cartridge homogenity Stability Duringthelifespanofthematerial,analysesaredoneeachmonth.Untilnow andinaccordancewiththefeasibilitystudy,nosignificantevolutionof concentrations was detected as is shown for example in Figures 4 and 5. Chemistry Statistics /Gas Analysis 9 Phial- Chlortoluron0.00000.02000.04000.06000.08000.10000.12003/24/2006 6/22/2006 9/20/2006 12/19/2006Concentration (mg/l )Figure 4. Stability of chlortoluron in solution in the vials DEA- Thimble0.000.100.200.300.400.500.603/24/2006 6/22/2006 9/20/2006 12/19/2006Concentration (g/l)Figure 5. DEA stability in cartridge Inter laboratory testing 16 laboratories with different techniques participated in this test (Table 2). Samples(3vialsand3cartridges)weresentonApril4th2006andallresults were received on May 20th 2006. VialCartridge10 Transverse Disciplines in Metrology LaboratoryAnalytical techniques Bouisson Bertrand LaboratoiresMMA/APO BRGM ORLEANSCTCPADpartement de l'conomie et de la Sant (DES)Service de Protection de la Consommation (SPCo) - GenevaIANESCOInstitut Dpartemental dAnalyse et de ConseilPle Organique de l'INERISISSeP (Institut de Scientifique de Service Public) - Belgium LECA / ESPCI LDA 22 Laboratoire Dpartemental DAnalyses de la Drme Laboratoire national de mtrologie et dessais (LNE) Micropolluants Technologie Nestl Waters MT Laboratoire chimie - PTC Waters Ple Analytique des Eaux /LABO/CEE Plouzan SGS Multilab Laboratoire de lEssonne CPL SM2(67% of participants) CPL UV (28% of participants) CPG TSD (5% of participants) CPG: gas chromatography,CPL: liquid chromatography,SM2: tandem mass spectrometry,TSD: thermoionic detector,UV: UV absorption.Table 2. Laboratories participing in the certification testing and implemented techniques ResultsRaw results for cartridges and vials are grouped in Tables 3 and 4 respectively. Chemistry Statistics /Gas Analysis 11 labo AtrazineDEA DIA SimazineTerburtryneTerbutylazineChlortoluronDiuronIsoproturonLinuron 0.093 0.082 0.079 0.093 0.106 0.094 0.118 0.104 0.114 0.116A 0.100 0.092 0.079 0.103 0.116 0.100 0.121 0.100 0.123 0.1230.095 0.083 0.084 0.096 0.109 0.099 0.128 0.097 0.120 0.1070.106 0.099 0.100 0.133 0.112 0.097 0.102 0.095 0.109 0.105B 0.110 0.101 0.102 0.137 0.116 0.102 0.109 0.098 0.111 0.1100.110 0.101 0.100 0.136 0.116 0.102 0.106 0.097 0.110 0.1100.076 0.054 0.076 0.100 0.066 0.042 0.105 0.114 0.107 0.057C 0.088 0.068 0.084 0.101 0.086 0.056 0.111 0.112 0.117 0.0750.096 0.077 0.087 0.103 0.107 0.068 0.112 0.111 0.119 0.0840.093 0.094 0.079 0.105 0.121 0.089 0.095 0.096 0.132 0.106D 0.095 0.103 0.079 0.105 0.123 0.095 0.111 0.096 0.106 0.1060.102 0.096 0.067 0.107 0.122 0.091 0.098 0.097 0.114 0.0950.111 0.097 0.094 0.130 0.128 0.105 0.107 0.100 0.121 0.111E 0.111 0.101 0.100 0.120 0.130 0.109 0.111 0.101 0.126 0.1310.107 0.093 0.095 0.126 0.125 0.106 0.109 0.096 0.117 0.1190.094 0.084 0.096 0.100 0.102 0.086 0.125 0.126 0.161 0.119F 0.093 0.082 0.093 0.100 0.093 0.085 0.115 0.117 0.145 0.1230.096 0.082 0.100 0.100 0.098 0.086 0.132 0.123 0.155 0.1240.102 0.097 0.096 0.116 0.134 0.105 0.119 0.110 0.130 0.119G 0.100 0.094 0.091 0.111 0.130 0.101 0.114 0.108 0.126 0.1160.104 0.099 0.097 0.117 0.136 0.106 0.121 0.111 0.132 0.1200.110 0.130 0.115 0.130 0.160 0.110 0.130 0.110 0.145 0.140H 0.110 0.135 0.110 0.130 0.150 0.110 0.130 0.110 0.145 0.1450.105 0.125 0.100 0.125 0.150 0.100 0.125 0.105 0.135 0.1400.109 0.098 0.070 0.130 0.138 0.100 0.117 0.105 0.130 0.121I 0.110 0.102 0.070 0.132 0.142 0.102 0.124 0.107 0.132 0.1100.113 0.106 0.076 0.142 0.145 0.107 0.134 0.110 0.139 0.1260.108 0.098 0.084 0.119 0.121 0.103 0.107 0.104 0.123 0.113J 0.108 0.098 0.084 0.119 0.123 0.104 0.107 0.104 0.124 0.1110.110 0.098 0.084 0.117 0.121 0.102 0.106 0.104 0.122 0.1140.114 0.115 0.103 0.112 0.109 0.091 0.129 0.109 0.133 0.138K 0.117 0.117 0.102 0.111 0.107 0.092 0.122 0.115 0.136 0.1260.133 0.140 0.113 0.121 0.138 0.106 0.152 0.117 0.147 0.1440.086 0.090 0.082 0.084 0.083 0.075 0.085 0.093 0.104 0.076M 0.085 0.083 0.081 0.087 0.082 0.072 0.087 0.086 0.099 0.0760.087 0.084 0.089 0.098 0.087 0.073 0.090 0.083 0.107 0.0870.108 0.118 0.154 0.116 0.165 0.135 0.115 0.155 0.113N 0.085 0.095 0.129 0.100 0.139 0.112 0.093 0.120 0.0980.107 0.103 0.163 0.109 0.154 0.130 0.106 0.140 0.1060.106 0.097 0.078 0.108 0.128 0.104 0.129 0.103 0.125 0.116O 0.105 0.097 0.079 0.108 0.129 0.104 0.133 0.103 0.127 0.1160.107 0.099 0.081 0.109 0.133 0.105 0.134 0.101 0.128 0.1170.120 0.099 0.162 0.113P 0.096 0.082 0.125 0.0860.115 0.104 0.148 0.112Table 3. Laboratory results for cartridges expressed in g/l of water Lab AtrazineDEADIASimazineTerburtryneTerbutylazineChlortoluronDiuronIsoproturonLinuron A 0.385 0.451 0.384 0.305 0.342 0.370 0.417 0.250 0.370 0.369A 0.400 0.466 0.410 0.328 0.395 0.382 0.423 0.226 0.429 0.416A 0.369 0.429 0.375 0.314 0.369 0.378 0.425 0.328 0.449 0.396B 0.415 0.503 0.457 0.442 0.393 0.421 0.393 0.400 0.454 0.429B 0.408 0.488 0.453 0.432 0.371 0.414 0.376 0.378 0.426 0.412B 0.419 0.522 0.473 0.447 0.379 0.417 0.388 0.387 0.438 0.428C 0.433 0.603 0.553 0.345 0.391 0.364 0.439 0.454 0.540 0.434C 0.423 0.511 0.502 0.334 0.383 0.350 0.425 0.441 0.530 0.418C 0.387 0.468 0.467 0.303 0.386 0.346 0.375 0.388 0.468 0.380D 0.336 0.424 0.320 0.304 0.392 0.352 0.312 0.372 0.388 0.368D 0.320 0.440 0.324 0.304 0.416 0.340 0.364 0.360 0.384 0.400D 0.324 0.368 0.308 0.420 0.336 0.360 0.404 0.428 0.384E 0.379 0.457 0.370 0.353 0.406 0.389 0.419 0.404 0.479 0.442E 0.384 0.455 0.414 0.366 0.417 0.399 0.433 0.398 0.492 0.464E 0.357 0.426 0.380 0.324 0.373 0.353 0.404 0.396 0.450 0.416F 0.341 0.448 0.469 0.300 0.368 0.312 0.352 0.436 0.556 0.388F 0.359 0.451 0.464 0.326 0.357 0.334 0.408 0.460 0.620 0.468F 0.321 0.408 0.427 0.300 0.326 0.307 0.416 0.500 0.624 0.432G 0.401 0.499 0.474 0.378 0.477 0.449 0.420 0.443 0.514 0.472G 0.391 0.504 0.485 0.374 0.471 0.430 0.427 0.452 0.530 0.468G 0.404 0.518 0.497 0.382 0.490 0.448 0.422 0.452 0.530 0.475H 0.405 0.565 0.395 0.360 0.480 0.450 0.405 0.415 0.525 0.455H 0.400 0.555 0.390 0.355 0.460 0.420 0.400 0.380 0.520 0.460H 0.430 0.565 0.390 0.370 0.490 0.435 0.400 0.405 0.520 0.470I 0.430 0.560 0.310 0.440 0.470 0.460 0.500 0.430 0.580 0.490I 0.420 0.420 0.258 0.420 0.380 0.460 0.450 0.390 0.450 0.500I 0.440 0.570 0.303 0.460 0.460 0.460 0.500 0.440 0.590 0.520J 0.422 0.500 0.400 0.389 0.422 0.434 0.368 0.404 0.481 0.429J 0.429 0.503 0.406 0.390 0.430 0.442 0.376 0.415 0.486 0.443J 0.430 0.501 0.392 0.394 0.442 0.447 0.377 0.425 0.491 0.449K 0.453 0.502 0.424 0.350 0.399 0.371 0.424 0.386 0.493 0.464K 0.434 0.451 0.440 0.339 0.402 0.348 0.432 0.382 0.502 0.466K 0.404 0.440 0.491 0.346 0.382 0.336 0.429 0.408 0.507 0.406L 0.330 0.400 0.390 0.340 0.380 0.360 0.380 0.300 0.460 0.280L 0.380 0.430 0.440 0.400 0.450 0.410 0.400 0.340 0.520 0.300L 0.360 0.420 0.470 0.350 0.420 0.410 0.380 0.300 0.500 0.340M 0.310 0.467 0.325 0.247 0.325 0.293 0.317 0.415 0.461 0.364M 0.332 0.453 0.351 0.261 0.338 0.308 0.331 0.438 0.484 0.354M 0.327 0.421 0.347 0.269 0.335 0.310 0.340 0.448 0.482 0.351N 0.454 0.538 0.485 0.451 0.435 0.426 0.439 0.543 0.424N 0.411 0.449 0.451 0.361 0.384 0.351 0.356 0.484 0.319N 0.441 0.462 0.401 0.390 0.396 0.373 0.388 0.501 0.361O 0.422 0.596 0.411 0.364 0.420 0.397 0.262 0.435 0.570 0.455O 0.463 0.631 0.428 0.388 0.449 0.443 0.270 0.446 0.599 0.485O 0.470 0.634 0.439 0.392 0.452 0.450 0.259 0.449 0.591 0.490P 0.378 0.321 0.508 0.328P 0.328 0.255 0.461 0.290P 0.288 0.259 0.391 0.277Table 4. Laboratory results for vials expressed in mg/l