trends in the identification of organic residues and contaminants: ec regulations under revision

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Trends in the identi¢cation of organic residuesand contaminants: EC regulations underrevisionFranc°ois AndreèLDH-LNR, Ecole Nationale Veèteèrinaire, P.O. Box 50707, F-44087 Nantes Cedex 03, France

Katia K.G. De Wasch, Hubert F. De Brabander*, Sandra R. ImpensGhent University, Faculty of Veterinary Medicine, Department of Veterinary Food Inspection,Laboratory of Chemical Analysis, Salisburylaan 133, B-9820 Merelbeke, Belgium

Linda A.M. Stolker, Leen van Ginkel, Rainer W. StephanyRIVM: European Union Community Reference Laboratory, A. Van Leeuwenhoeklaan 9, P.O. Box 1,NL-3720 BA Bilthoven, The Netherlands

Robert SchiltTNO Nutrition and Food Research, Department of Residue Analysis, Product Group Hormones andVeterinary Drugs, P.O. Box 360, 3700 AJ Zeist, The Netherlands

Dirk CourtheynState Laboratory Ghent, Braemkasteelstraat 49, B-9050 Gentbrugge, Belgium

Yves BonnaireLaboratoire du LAB / FNCF, Avenue de la division Leclerc 169, F-92290 Chatenay Malabry, France

Peter FuërstChemical and Veterinary Control Laboratory, D-48151 Muënster, Germany

Petra GowikBgVV: European Union Community Reference Laboratory, Diedersdorfer Weg 1, D-12277 Berlin, Germany

Glenn KennedyDepartment of Agriculture and Rural Development, Veterinary Sciences Division, Stoney Road,Stormont, Belfast BT4 3SD, UK

Thomas KuhnFederal Veterinary Institute, Robert Koch Gasse 17, A-2340 Moëdling, Austria

Jean-Pierre MoretainAFSSA-Laboratoire d'Etudes et de Recherche sur les Meèdicaments, Veèteèrinaires et les Deèsinfectants,P.O. Box 90203, Javeneè, 35302 Fougeéres, France

Maurice SauerDepartment of Risk Research, Veterinary Laboratories Agency, New Haw, Addlestone KT15 3NB, UK

0165-9936/01/$ ^ see front matter ß 2001 Elsevier Science B.V. All rights reserved.PII: S 0 1 6 5 - 9 9 3 6 ( 0 1 ) 0 0 0 8 5 - 1

*Corresponding author. Tel.: +32 (9) 2647460; Fax: +32 (9) 264 7492.E-mail: [email protected]

trends in analytical chemistry, vol. 20, no. 8, 2001 435

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The use of identi¢cation points ( IPs) is a newapproach to set up quality criteria for the identi¢-cation of organic residues and contaminants: alaboratory is allowed to use any molecular spectro-metric technique or combination of techniques inorder to earn a minimum number of points. Thesystem of IPs balances the identi¢cation power ofthe different analytical techniques and has theadvantage that new techniques can be introducedvery easily. z2001 Elsevier Science B.V. All rightsreserved.

Keywords: Residue; Veterinary drug; Analysis; Qualitycriterion; Identi¢cation point; Legislation; Contaminant

1. Introduction

In the European Union the European Commis-sion regulates the inspection of animals and freshmeat for the presence of residues of veterinarydrugs and speci¢c contaminants (Council Directive86/469/EEC, subsequently replaced by 96/23/EC) [ 1,2 ]. The quality criteria for the analysis ofsuch residues are described in a series of Commis-sion Decisions [ 3,4 ]. These legislative decisions arerevised periodically to take into account currentscienti¢c knowledge and the latest technicalimprovements. The two Decisions effective sinceApril 1993 are 93/256/EEC and 93/257/EEC[ 4,5 ] and should have been revised in 1996. Inaccordance with the Council Directives, an exten-sive network of analytical residue laboratories hasbeen created for the purpose of veterinary inspec-tions. This network consists of a hierarchical sys-tem of so-called routine and /or ¢eld laboratories(RFLs), about 40 national reference laboratories(NRLs) and four communities reference laborato-ries (CRLs). An overview of this strategic system oflaboratories is presented elsewhere [ 6 ].

In 1995, in co-operation with the four CRLs, theCommission started the complete legal and techni-cal revision of the two criteria Decisions [ 4,5 ]. Dueto the complex nature of the revision process, theconcurrent revision of the underpinning CouncilDirective 86/469/EEC and, last but not least, thedemand for a stronger participation of the NRLs inthe process, in May 1998 the Commission desig-nated a working group to draft new or revised cri-teria. This working group was chaired by Franc°oisAndreè (Nantes, France) and supervised by theCommission and the four CRLs.

The working group was also requested to takeinto account the developments and progressmade in related ¢elds globally [ 7 ], e.g. within therelevant Committees of the FAO/WHO Codex Ali-mentarius and the control of doping in sports.

During the discussions in the working group theconcept of identi¢cation points ( IPs ) for setting upquality criteria for qualitative methods (or the qual-itative part of quantitative methods) was intro-duced and accepted. The basic idea of IPs is that alaboratory is allowed to use any molecular spectro-metric technique or combination of techniques inorder to obtain the minimum number of IPs neces-sary for the proper identi¢cation of a component.The minimum number of points that must beobtained for group A ( banned) compounds is setto four. This number corresponds to the classicalfour ions ( in correct ratios) of electron ionisation(EI ) mass spectrometry [ 4 ].

However, a laboratory is not restricted to fourpoints and may identify a component using moreIPs, provided that this procedure does not producea higher false negative rate. For compounds with anestablished maximum residue limit (MRL) (groupB), a minimum of three IPs are required for satis-factory con¢rmation of the compound's identity. Inthis paper, in which all members of the workinggroup participated, some of the aspects and back-ground of the use of IPs are presented.

2. Limitations of current criteria

The current European criteria [ 3 ] require thatwhen gas chromatography coupled to low resolu-tion mass spectrometry (GC^LRMS) is used as acon¢rmatory method, it is preferred that the inten-sities of at least four diagnostic ions are measured. Ifthe compound does not yield four diagnostic ionswith the method used, the identi¢cation of the ana-lyte should be based on the results of at least twoindependent GC^LRMS methods with differentderivatisation and /or ionisation techniques, eachproducing two or three diagnostic ions. The molec-ular ion should preferably be one of the selecteddiagnostic ions. The relative abundances of all diag-nostic ions of the analyte should match those of thestandard analyte, preferably within a margin ofþ 10% (EI mode) or þ 20% (chemical ionisation(CI) mode).

The most important limitations of these rules arethreefold: (1) the criteria are not applicable to all

436 trends in analytical chemistry, vol. 20, no. 8, 2001

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compounds, (2 ) the criteria are ambiguous, (3)application of the criteria is limited to GC^MS.

First, not all group A compounds (e.g. someL-agonists ) generate four suitable diagnostic ions.Depending on the structure of the molecules someanalytes show only two or three diagnostic ions. Insuch cases much time is spent on testing alternativederivatives in order to obtain the necessary ions forproper identi¢cation. Even if a component showsfour diagnostic ions at a relatively high concentra-tion ( s 2 Wg /kg), the less abundant ions may dis-appear when the concentration of the analytedecreases, creating false negative results accordingto the criteria. This is easily demonstrated by using aseries of spiked samples.

The most important factor is the interpretation ofthe tolerance of the peak intensity ratios. For exam-ple: some analysts have interpreted the tolerancesof ion ratios as being absolute (þ 10%). When con-sidering a spectrum consisting of one major diag-nostic ion and three minor ones and interpreting thetolerances as absolute, the smaller ions may varywidely (e.g. between 1 and 21%). These tolerancesare so wide that the spectrum will easily match thecriteria if the major peak is present and lower inten-sity `peaks' result only from noise.

Mass spectrometric detection can be carried outby recording full mass spectra for example by MSn

techniques (e.g. in ion traps) or by selected ionmonitoring (SIM) and selected reaction monitoring(SRM) (e.g. in quadrupoles). Other MS or MSn tech-niques in combination with separation techniques(column liquid chromatography (LC) or GC) andionisation modes (e.g. EI, CI, atmospheric pressurechemical ionisation, electrospray ionisation (ESI ))can be used as well. The criteria for mass spectrom-etry in 93/256/EEC are not really adequate giventhe technical advances that have occurredrecently.

3. Some `new' de¢nitions in£uencingquality criteria and IPs

3.1. New de¢nitions of analytical parameters

In the draft revision of 93/256/EEC (since 2000referred to as Commission document SANCO/1805/2000), de¢nitions which may in£uence theuse of IPs are discussed brie£y. For example, amethod is only considered quantitative if criteriafor accuracy (sum of trueness and precision) are

ful¢lled. It is also highlighted that the identi¢cationof compounds has to be completed before theirquanti¢cation. The de¢nitions of the analytical lim-its will now be based on the detection capability(CCL: the smallest content of the analyte identi¢edby a speci¢ed set of identi¢cation parameters ( so-called `identi¢ers'), IPs inclusive, that may bedetected or quanti¢ed in a sample with an errorprobability of L ( likelihood of a false negative deci-sion; L-error95%)) and on the decision limit (CCK:the limit at which the content of the analyte in asample is truly violative with an error probabilityof K ( likelihood of a false positive decision)),replacing the formerly used limits of detection,determination and quanti¢cation. Some termshave been changed for regulatory reasons, `viola-tive result' replacing `positive result', and `non-vio-lative result' replacing `negative result'. In addition,a new regulatory limit was established, the `mini-mum required performance limit' (MRPL: the con-tent at which the method will give reliable results interms of violative and non-violative). This will har-monise the minimum performance characteristicswhich European residue control laboratories mustachieve in their analytical methods for banned sub-stances. This level has to be established for eachanalyte^matrix combination in accordance withCouncil Directive 96/23/EC by the Commissionin close co-operation with the four CRLs and servesthe harmonisation of the performance levels ofthose laboratories.

3.2. Ion recognition

Ions must be de¢ned in full-scan or mass frag-mentography (SIM).

If mass spectrometric determination is performedby recording full-scan spectra, the presence of allmeasured diagnostic ions with a relative intensity ofmore than 10% in the reference spectrum of thestandard analyte is obligatory.

If mass spectrometric determination is performedby fragmentography, the molecular ion shouldpreferably be one of the selected diagnostic ions.The selected diagnostic ions should not exclusivelyoriginate from the same part of the molecule. Thesignal-to-noise ratio for each diagnostic ion must bev 3:1. The relative intensities of the detected ions,expressed as a percentage of the intensity of themost intense ion or transition, must correspond tothose of the standard analyte, either from calibra-tion standards or from spiked samples, at compara-


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ble concentrations and measured under the sameconditions, within the tolerances given in Table 1.

Whenever a background correction is carriedout, this must be performed uniformly throughoutthe batch.

3.3. Interpretation of mass spectral data

Mass spectrometric methods are suitable for con-sideration as con¢rmatory and /or reference meth-ods only following either an on-line or an off-linechromatographic separation.

If full-scan spectra are recorded in single MS, aminimum of four diagnostic ions must be presentwith a relative intensity of v 10% of the base peak.The molecular ion should be included if it is presentin the reference spectrum with a relative intensity ofv 10%. Computer-aided library searching may beused instead of visual comparison. In this case, thecomparison of the mass spectral data in the testsamples to that of the standard analyte must exceeda critical match factor (e.g. 900/1000 for a reversed¢t search). This factor should be determined duringthe validation process for every analyte on the basisof spectra for which the criteria described below areful¢lled.

4. Quality criteria and IPs

If mass fragments are measured, a system of IPsshall be used to interpret the data. For the con¢rma-tion of group A and B substances, a minimum offour respectively three IPs is required. Table 2shows the number of IPs that each of the basicmass spectrometric techniques can earn. However,in order to qualify for the IPs, a minimum of at leastone ion ratio must be measured, all measured ionratios must meet the criteria described above, anda maximum of three separate techniques can becombined to achieve the minimum number of IPs.

In determining the number of IPs the followingremarks should be taken into account: of courseeach ion may only be counted once. GC^MSusing EI is regarded as being a different techniqueto GC^MS using CI. Different chemical derivativesof an analyte can be used to increase the number ofIPs only if derivatisation is based on different reac-tion chemistries (e.g. trimethylsilyl and hepta£uo-robutyryl derivatives ). For the ¢nal con¢rmation ofsubstances listed in group A, the selected methodsmust involve the use of mass spectrometry. How-ever, since some analytes yield only three ions, thefollowing techniques can be used to contribute amaximum of one IP: LC coupled with full-scandiode array spectrophotometry (DAD), LC coupledwith £uorescence detection, LC coupled with animmunogram or two-dimensional TLC coupledwith spectrometric detection, providing that the rel-evant criteria for these techniques (described inSANCO/1805/2000) are ful¢lled.

In Table 3 some examples of the number of IPsthat can be earned for a range of techniques andtheir combinations are given.

Fig. 1. Format to report IPs.

Table 2Relationship between nature of MS information and IPs earned

MS technique IPs earned per ion

Low resolution mass spectrometry (LR) 1.0LR^MSn precursor ion 1.0LR^MSn transition products 1.5High resolution mass spectrometry (HR) 2.0HR^MSn precursor ion 2.0HR^MSn transition products 2.5

Table 1Maximum permitted tolerances for various relative ion intensities

Relative intensitya GC^EI^MSb Other techniquesc

s 50% þ 10% þ 20%s 20^50% þ 15% þ 25%s 10^20% þ 20% þ 30%9 10% þ 50% þ 50%

aRelative intensity ( in % of base peak).bTolerance relative to relative intensity ( in % of peak intensity ).cGC^CI^MS, GC^MSn , LC^MS, LC^MSn .


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The practical application of IPs may be per-formed by computer programs. In Fig. 1 an exampleof a datasheet of a violative result is given.

5. Examples of the application of IPs

The following examples describe the applicationof the IP concept in residue analysis.

Fig. 2. LC^MS2 chromatogram and spectra of a `violative' sample (16L-hydroxystanozolol ); precursor ion: m / z 345.5.

Table 3Examples of number of IPs earned for a range of techniques and their combinations

Technique Number of ions IPs

GC^MS (EI or CI) n nGC^MS (EI and CI ) 2 (EI)+2 (CI ) 4GC^MS (2 derivs) 2 (derivative A)+2 (derivative B) 4LC^MS n nGC^MS^MS 1 precursor and 2 product ions 4LC^MS^MS 1 precursor and 2 product ions 4GC^MS^MS 2 precursor ions, each with 1 product 5LC^MS^MS 2 precursor ions, each with 1 product 5LC^MS^MS^MS 1 precursor, 1 product and 2 second transition products 5.5HRMS N 2nGC^MS and LC^MS 2+2 4GC^MS and GC^HRMS 2+2 4


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Fig. 3. LC^MS2 chromatograms of nicarbazin (DNC) in standards and chicken liver.

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5.1. Anabolic steroids: 16Þ-hydroxystanozolol

The abuse of stanozolol (a group A component )in cattle fattening is detected by the determinationof the major bovine metabolite (16L-hydroxystano-zolol ) by LC^MSn [ 8,9 ]. Fig. 2 shows the chromato-gram and spectrum of a `violative' sample.

In Table 4 the calculation of IPs for 16L-hy-droxystanozolol is presented. The parametersneeded are: the relative intensities of ions to thebase peak ( m /z 159) in the MS2 (product ion)spectrum of a spiked sample; the maximum permit-ted tolerances for relative ion intensities (calculatedfrom Table 1). The relative intensities which matchthe tolerances are marked with a `#'. As can be seenin Table 4, the calculated number of IPs for theblank sample (non-violative sample) is one( there are no ions, except the base peak, whichmatch the tolerances). For the violative samples10 and 13 IPs are calculated, respectively. Thisnumber of IPs is clearly higher than the minimumnumber that has to be earned.

Fig. 4. LC^MS2 chromatogram and spectra of a `violative' sample (clenbuterol ).

Table 4Calculation of IPs for 16L-hydroxystanozolola

m / z Spike Tolerance Blankb Sample 1c Sample 2d

107 28 (21^35) 4 46 25121 37 (28^46) 1 40 40133 49 (37^61) 2 40 40145 40 (30^50) / 36 47159 100 (80^120) 7 100 97173 61 (49^73) 4 75 59189 35 (26^44) 7 38 45201 46 (35^58) 1 51 52227 88 (70^106) 100 69 100

IPs C 1 10 13

Relative intensity within tolerance.aParameters needed: relative intensities of ions to base peak andtolerances in blank sample forti¢ed with the analyte; relativeintensities to base peak in a blank, a non-violative and two vio-lative samples.bBlank (non-violative sample).cSample 1: violative sample ( low concentration).dSample 2: violative sample (higher concentration).


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5.2. Þ-Agonists: clenbuterol

Clenbuterol (a group A compound) is the mostpopular L-agonist in cattle fattening and is also usedin sports doping. Fig. 3 shows an example of thedetermination of clenbuterol by LC^MS2 [ 10 ]; onlytwo diagnostic MS2 ions are available. The mini-mum criteria for identi¢cation are reached by oneprecursor ion ( m /z 277: 1 IP) and two product ions(at m /z 203 and 259: 3 IPs) which match the toler-ances of the ion ratios calculated on the basis of aspiked sample.

5.3. MRL compound: nicarbazin

Nicarbazin, a coccidiostat, consists of 4,6-dimethyl-2-hydroxypyrimidine and 4,4P-dinitrocar-banilide (DNC), complexed in a 1:1 molar ratio.The Joint FAO/WHO Expert Committee on FoodAdditives ( JECFA) has ¢xed an MRL of 200 Wg /kgfor DNC in the liver, kidney, muscle, fat or skin of

broiler chickens. As a group B substance, three IPsare required for the con¢rmation of DNC. However,the LC^ESI MS^MS method employed [ 11 ] earnsfour IPs. In addition to the molecular ion [M3H]3

at m /z 301 (1 IP), two transition ions at m /z 137and 107 (3 IPs), and their corresponding ratios aremonitored. These transitions correspond to scission(cleavage) of the molecule and loss of NO, as indi-cated in Fig. 4. This ¢gure also shows SRM traces ofa standard (100 Wg /kg, equal to half the JECFAMRL), a negative liver sample and an incurredliver sample containing 106 Wg /kg. Traces at m /z309, corresponding to the internal standard d8-DNC, are also shown.

5.4. MRL compound: avermectins and moxidectin

Avermectins and moxidectin are widely used inanimal husbandry against nematode and arthropodparasites. A multi-residue method was developedand validated for the quantitation and con¢rmation

Fig. 5. GC^MS2 chromatogram and spectra of PCB 52 in a fat sample compared to a spike and PCB 52 (13 C) internal standard.


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of avermectins and moxidectin residues in bovineliver using ( ion-trap) LC^MS2 (Table 5) [ 12 ].

The high mass of the precursor and product ionsreduces the probability that matrix components willproduce isobaric interferences and the product ions

selected should guarantee reliable con¢rmation asthey derive from different parts of the parent mole-cule. The daughter ions were all detected withsignal to noise ratios of s 3:1 at concentrations atleast an order of magnitude below their MRLs (10^

Table 5Ions used for con¢rmation of the avermectins and moxidectin using LC^MS2

Compound Parent ion m / z [M3H ]3 Higher mass daughter ion Lower mass daughter ion Ratio of peak heightsa

Eprinomectin 912.5 830.6 565.4 1.7 (29%)Abamectin 871.5 789.6 565.4 2.1 (23%)Doramectin 897.5 815.6 591.5 2.1 (19%)Moxidectin 638.4 594.5 528.5 1.5 (24%)Ivermectin 873.5 791.6 567.5 2.7 (17%)

aValues in parentheses are RSDs (n=144).

Fig. 6. HRGC^HRMS chromatograms of 2,3,7,8-TCDD in cow's milk.


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40 Wg /kg), thus allowing a substantial margin forcon¢rmation at the respective decision limits(CCK ).

The higher mass product ion has less than 10%of the intensity of the precursor ion for all analytesand consequently a tolerance window of 50% wasadopted. The ratios obtained with forti¢ed andincurred samples were invariably within this toler-ance when compared with standards of the sameconcentration analysed in the same batch. Themethod earns four IPs, exceeding the requirementsfor identi¢cation of licensed substances ( threeIPs).

5.5. Contaminants: polychlorobiphenyls (PCBs )and dioxins

PCBs are well-known contaminants that mayenter the food chain. Their presence is monitoredby the analysis of seven marker congeners in fatsamples by GC^MS2. Fig. 5 shows a chromatogramand MS2 spectra of PCB 52 (one of the seven con-geners) in a fat sample are given [ 13 ]. Identi¢cationis effected by one precursor ion ( m /z 292: 1 IP)and three product ions with two ratios betweenthem matching the tolerances (at m /z 220, 222and 257: 4.5 IPs) yielding a total of 5.5 IPs.

Fig. 6 shows the determination of 2,3,7,8-TCDDin cow's milk at a concentration level of 0.30 pg /gfat.

The upper two fragmentograms show the tracesfor native TCDD and the lower two the traces for the13C-labelled internal standards. The analysis wasperformed HRGC/HRMS at a resolution ofRs=10 000. The target ratio for the two ions(319.8965 and 321.8936) monitored is 0.76. Ascan be seen all requirements (4 IPs from twoHRMS ions) are ful¢lled [ 14 ].

6. Conclusions

The use of IPs is a new approach to set up qualitycriteria for the identi¢cation of organic residues andcontaminants. The system of IPs balances the iden-ti¢cation power of the different analytical tech-niques and moreover has the advantage that newtechniques may easily be incorporated in the pro-cedure. The authors hope that this contributionmay help in the general understanding, further test-ing and validating, and acceptance of this principleonce the new criteria have been published.

The new criteria were discussed and adopted bythe NRLs during a workshop in 1999 at Bilthoven(The Netherlands). The Commission documentSANCO/1805/2000 was adopted by the CRLs inearly 2000 and distributed in late 2000 to the EUMember States for legal comments. At present, thedocument ^ which may have far-reaching conse-quences for trade ^ is being circulated within thevarious involved Directorates General of the Com-mission for advice, consultation and approval.

Meanwhile many laboratories involved in theCRL^NRL^RFL network have already implementedthe new criteria and in March 2000 the concept wasalso formally submitted by the Commission to theFAO/WHO Codex Alimentarius for consideration.

Acknowledgements

The authors wish to thank Ms Claire Gaudot ( for-mer DG VI) and Mr Jordi Serratosa (DG SANCO)for their interest in the revision of the criteria andtheir support of the working group.

References

[ 1 ] Council Directive 86/469/EEC of 16 September 1986concerning the examination of animals and fresh meatfor the presence of residues. Off. J. Eur. Communities L275 (1986) 36.

[ 2 ] Council Directive 96/23/EC of 29 April 1996 on meas-ures to monitor certain substances and residues thereofin live animals and animal products and repealingDirectives 85/358/EEC and 86/469/EEC and Deci-sion 89/187/EEC and 91/664/EEC. Off. J. Eur. Com-munities L 125 (1996) 10.

[ 3 ] Commission Decision 89/610/EEC of 14 November1989 laying down the reference methods and the listof national laboratories for detecting residues. Off. J.Eur. Communities L 351 (1989) 39.

[ 4 ] Commission Decision 93/256/EEC of 14 April 1993laying down the methods to be used for detecting res-idues of substances having a hormonal or a thyreostaticaction. Off. J. Eur. Communities L 118 (1993) 64.

[ 5 ] Commission Decision 93/257/EEC of 15 April 1993laying down the reference methods and the list ofnational reference laboratories for detecting residues.Off. J. Eur. Communities L 118 (1993) 75.

[ 6 ] R.W. Stephany, J. Boiseau, B. Julicher, S. Caroli, in: N.Haagsma, A. Ruiter (Editors ), Proc. EuroResidue IIIConference, Veldhoven, 6^8 May, 1996, p. 149.

[ 7 ] R.W. Stephany, in: L.A. van Ginkel, A. Ruiter (Editors),Proc. EuroResidue IV Conference, Veldhoven, 8^10May, 2000, p. 137.

[ 8 ] P. Delahaut, X. Taillieu, M. Dubois, K. De Wasch, H.F.


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De Brabander, P. Batjoens, D. Courtheyn, Arch. Le-bensmittelh. 49 (1998) 3.

[ 9 ] H.F. De Brabander, K. De Wasch, L.A. van Ginkel, S.S.Sterk, M.H. Blokland, P. Delahaut, X. Taillieu, M.Dubois, C.J.M. Arts, M.J. van Baak, L.G. Gramberg, R.Schilt, E.O. van Bennekom, D. Courtheyn, J. Vercam-men, R.F. Witkamp, Analyst 123 (1998) 2599.

[ 10 ] K. De Wasch, H.F. De Brabander, D. Courtheyn, Ana-lyst 123 (1998) 2701.

[ 11 ] S. Yakkundi, A. Cannavan, C.T. Elliott, T. Loëvgren, D.G.Kennedy, Analyst (2000) submitted for publication.

[ 12 ] L. Howells, M.J. Sauer, in: L.A van Ginkel, A. Ruiter(Editors ), Proc. Euroresidue IV Conference, Veld-hoven, 8^10 May, 2000, p. 575.

[ 13 ] S. Impens, K. De Wasch, H.F. De Brabander, B. deMeulenaere, A. Huyghebaert, S. de Saeger, A. Heere-mans, C. van Peteghem, M. Logghe, D. Courtheyn, R.van Renterghem, in: L.A. van Ginkel, A. Ruiter (Edi-tors), Proc. EuroResidue IV Conference, Veldhoven,8^10 May, 2000, p. 627.

[ 14 ] P. Furst, unpublished results.

Franc°ois Andreè is professor in the Ecole Nationale VeèteèrinaireNantes, Laboratoire des dosages hormonaux, Nantes, France. TheLDH is the National Reference Laboratory (NRL) in the frameworkof EU control of organic residues and contaminants.

Hubert De Brabander is professor of analytical chemistry of foodin the Department of Veterinary Food Inspection, Laboratory ofChemical Analysis, Veterinary Faculty of Ghent University,Ghent, Belgium. Katia De Wasch and Sandra Impens areresearchers in the same department.

Leen van Ginkel and Rainer Stephany are respectively the deputydirector and the director of the European Union CommunityReference Laboratory at the National Institute of Public Healthand the Environment (RIVM) in Bilthoven, The Netherlands.

Linda Stolker is a researcher in the same department. RainerStephany is also professor of analytical chemistry at the Departmentof the Science of Food of Animal Origin, Veterinary Faculty ofUtrecht University, Utrecht, The Netherlands.

Robert Schilt is senior chemist and deputy study director and assuch is responsible for the con¢rmatory analysis of growth promotingsubstances at the TNO Nutrition and Food Research in Zeist, TheNetherlands.

Dirk Courtheyn is responsible for the analysis of growthpromoting substances at the State Laboratory of the Ministry ofAgriculture, Gentbrugge, Belgium.

Yves Bonnaire is director of the French National Laboratory fordoping control on racehorses, France.

Peter Fuërst is head of the Department for Central AnalyticalServices of the Chemical and Veterinary Control Laboratory inMuënster, Germany.

Petra Gowik is the acting director of the Community ReferenceLaboratory and the National Reference Laboratory for residues ofveterinary drugs at the Federal Institute for Health Protection ofConsumers and Veterinary Medicine (BgVV) in Berlin.

Glenn Kennedy is responsible for the con¢rmatory analysis of allclasses of veterinary drug residues. He is employed in one of the UKNational Reference Laboratories for veterinary drug residueanalysis.

Thomas W. Kuhn is head of the section for growth promotingagents of the National Reference Laboratory at the FederalVeterinary Institute in Moëdling, Austria.

Jean-Piere Moretain is scienti¢c manager of the French NationalReference Laboratory for veterinary drug residues, which is part ofthe Agency for Food Safety (AFSSA) and is located in Fougeéres,France.

Maurice Sauer is head of the Metabolism and Protein BindingGroup, Department of Risk Research, Veterinary LaboratoriesAgency, New Haw, Addlestone, Surrey KT15 3NB, UK.


trends in the identification of organic residues and contaminants: ec regulations under revision

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