Dr. André de Kok

Curriculum Vitae Dr. André de Kok and Organization profile
Dr. André de Kok
Date and place of birth: 6 March 1954, Amsterdam
Organization Name and mailing address:
Food and Commodity Authority/Food Inspection Service
Chemistry Laboratory - R&D Pesticide Analysis Group
Hoogte Kadijk 401
1018 BK Amsterdam -The Netherlands
Tel: +31 20 5244711
Fax: +31 20 5244700
E-mail: andre.de.kok@vwa.nl
General information
The VWA – Food and Consumer Product Safety Authority is an executive enforcement and
research agency of the Dutch Ministry of Agriculture, which consists, since the reorganization of
1998, of 1 head office and 5 regional inspection offices/laboratories. The Northwest region, located
in Amsterdam, is specialised in the analysis of primary agricultural and horticultural products (i.e.
non-fatty products, no veterinary products). The refurbished (since 1/11/1999) laboratory may be
considered as one of the most experienced laboratories in Europe for, in particular, pesticide residue
analysis in agricultural and related processed food products.
The major task of the VWA is the enforcement and promotion of compliance with regulations
pertaining to food products as laid down in various laws, such as the Food Law and the Pesticide
Law. The VWA is, amongst others, responsible for the Dutch contribution to the EU monitoring
programme for pesticide residues in fruits, vegetables and cereals. The VWA is also responsible for
the import (EU border) control of products originating from third countries. The Rotterdam harbour
and Amsterdam Schiphol Airport are important inspection and control points for both monitoring
and enforcement purposes
C.V. of Dr. André de Kok
Dr. André de Kok got his Masters’ degree in (Analytical) Chemistry at the Free University
Amsterdam, in 1979, and finished his Thesis (“GC and LC Determination of Polyhalogenated
Aromatics and Phenylurea Herbicides in Environmental Samples”) on an environmental analytical
topic, and received his Ph.D. degree, in 1983, at the same University. He has been working with the
Food Inspection Service in Alkmaar since 1983, starting in the Tobacco Analysis Specialisation and
continuing, since 1985, as Head of the Pesticide Analysis Department. Besides the responsibilities
for the routine enforcement and monitoring work, he has been specialising in the development,
validation and implementation of analytical methods for pesticide residues in fruits and vegetables,
focussing on multi-residue methods using advanced sample preparation, GC and LC separation
methods and specific detection techniques.
Since September 1998, he has now a position as Senior Analytical Chemist in the Research and
Development Group of the Chemistry Laboratory of the VWA – Food and Consumer Product
Safety Authority, in Amsterdam, with the main responsibility for pesticide analysis methods, both
Single- and multi-residue methods, based on chromatographic (GC and LC) techniques. These
methods are implemented in the routine analytical screening of the Central Pesticide Analysis team
or applied in separate surveys.
He is also responsible for and involved with quality assurance, quality control and proficiency
testing of all pesticide residue analyses applied. He is project leader for all yearly analytical projects
in the field of pesticide residue analysis. The laboratory in Amsterdam is equipped with modern
GC-ECD/NPD/FPD, GC-MS(/MS), and LC-UV/DAD/Fluorescence and LC-MS/MS separation

and detection systems. The pesticide laboratory in Amsterdam has been assigned as National
Reference Laboratory for pesticide residues, in The Netherlands.
Dr. De Kok has been author and/or co-author of more than 25 papers in scientific journals and has
presented many lectures and posters at international symposia and workshops.
Dr. De Kok was the chairman of the 1st European Pesticide Residue Workshop (EPRW’96), held in
Alkmaar, The Netherlands, June 1996. He is still a member of the Scientific Organising Committee
of the biannual EPRW.
Dr. De Kok has cooperated in a EU Quality Control Project resulting in an EU document “Quality
Control Procedures for Pesticide Residues Analysis” (Guidelines for Residues Monitoring in the
EU), that has been revised biannually and he was a member of the scientific/organising committee
of EU Workshops on Coordinated Analytical Quality Control (for Pesticide Residue Analysis),
held in Oeiras (Lisbon), Portugal (September 1997), Athens, Greece (November 1999), York, UK
(July 2003) and Stockholm, Sweden (December 2005).
Dr. De Kok is also a member of the Advisory and Scientific Committee for EU Proficiency Testing
for EU Member State laboratories submitting pesticide residue data as part of the EU Monitoring
programme for pesticide residues in fruits and vegetables.
Dr. De Kok has been participating in two other EU SMT projects on “Organophosphorus Pesticides
in Cereals” and “Intercomparison study of three CEN extraction methods for pesticide residue
analysis’, respectively, and he has co-organised two collaborative studies for the validation of
(draft) CEN-standardised methods for the analysis of N-methylcarbamate pesticides and
benzimidazole fungicides, respectively. Both methods were developed in the Pesticide Analysis
Department of the former Alkmaar Food Inspection Service (now VWA).
He is participating as an governmental liason, experienced pesticide analysis laboratory in a 2-year
EU Alfa-programme project “EUROLANTRAP” (The development of fast and cost-effective
harmonized analytical methods for the determination of pesticides residues in fruits, vegetables and
cereals, to be applied for import and export control, in order to reduce trade barriers and the health
risks for consumers) between 3 Latin-American and 3 European universities, promoting the
exchange of Professors, tutors,Master and Ph.D. students between LA and Europe.
He was co-author of the well-known Dutch Manual “Analytical Methods for Pesticide Residues in
Foodstuffs” (6 th Edition, 1996, General Inspectorate for Health Protection, The Hague, The
Netherlands), to which his laboratory contributed many advanced multi-residue methods.
Most recent literature references:
1. A. de Kok, M. Hiemstra and C.P. Vreeker
Improved cleanup method for the multiresidue analysis of N-methylcarbamates in grains, fruits and
vegetables by means of HPLC with post-column reaction and fluorescence detection
Chromatographia, 24 (1987) 469-476.
2. A . de Kok, M. Hiemstra and C.P. Vreeker
Optimization of the postcolumn hydrolysis reaction on solid phases for the routine high-performance liquid
chromatographic determination of N-methylcarbamate pesticides in food products
J. Chromatogr., 507 (1990) 459-472.
3. A. de Kok, M. Hiemstra and U. A. Th. Brinkman
Low ng/l-level determination of twenty N-methylcarbamate pesticides and twelve of their polar metabolites
in surface water via off-line solid-phase extraction and high-performance liquid chromatography with postcolumn
reaction and fluorescence detection
J. Chromatogr., 623 (1992) 265-276.
4. A. de Kok and M. Hiemstra
Optimization, automation, and validation of the solid-phase extraction cleanup and on-line liquid
chromatographic determination of N-methylcarbamates in fruits and vegetables
J. AOAC Int., 75 (1992) 1063-1072.

5. M. Hiemstra and A. de Kok
Determination of N-methylcarbamate pesticides in environmental water samples using automated on-line
trace enrichment with exchangeable cartridges and high-performance liquid chromatography
J. Chromatogr., 667 (1994) 155-166.
6. A. de Kok
Multiresidue methods used in The Netherlands and residue data obtained in 1993
Proceedings of the 3rd International Seminar on Pesticide Residues, Almeria, Spain (1994), 87-113.
7. A. de Kok, C.P. Vreeker, E.W. Besamusca, A.A. Toonen and M. Hiemstra
“Evaluation, validation and practical application of GC-ITD for routine pesticide residue analysis in fruits
and vegetables”,
in: ‘Current Status and Future Trends in Analytical Food Chemistry”, Proceedings of the Eighth European
Conference on Food Chemistry (Euro Food Chem VIII), Vienna, Austria (1995), Volume 2, 415-418.
8. M. Hiemstra, J. A. Joosten and A. de Kok
Fully automated solid-phase extraction cleanup and on-line liquid chromatographic determination of
benzimidazole fungicides in fruit and vegetables
J. AOAC Int., 78 (1995) 1267-1274.
9. Co-author of: “Analytical Methods for Pesticide Residues in Foodstuffs”, 6th edition (1996), Inspectorate
for Health Protection, Ministry of Health, Welfare and Sports, The Hague, The Netherlands.
10. M. Hiemstra, A.A Toonen and A. de Kok
Determination of benzoylurea insecticides in pome fruit and fruiting vegetables using liquid chromatography
with diode array detection, and residue data obtained in the Dutch national monitoring program
J. AOAC Intern., 82 (1999) 1198-1205.
11. M. Hiemstra and A. de kok
Determination of pesticides using liquid chromatography-mass spectrometry;
I. Analytical method for imidacloprid – Survey of agricultural products
De Ware(n)-Chemicus, 31(2001)115-128.
12. M. Hiemstra and A. de kok
Determination of pesticides using liquid chromatography-mass spectrometry;
II. Analytical method for propamocarb – Survey of agricultural products
De Ware(n)-Chemicus, 31(2001)215-227.
13. M. Hiemstra and A. de Kok
Determination of propamocarb in vegetables using polymer-based high-performance liquid chromatography
coupled with electrospray mass spectrometry
J. Chromatogr. A, 972(2002)231-239.
14. S.J. Lehotay, A. de Kok, M. Hiemstra, P. van Bodegraven, Validation of a Fast and Easy Method for the
Determination of 229 Pesticide Residues in Fruits and Vegetables Using Gas and Liquid Chromatography
and Mass Spectrometric Detection,
J. AOAC Int. 88 (2005)595.
15. A. Agüera and A. de Kok, in: A.R. Fernández-Alba (Ed.), Chromatographic - Mass Spectrometry Food
Analysis for Trace Determination of Pesticide Residues, Vol. XLIII, Elsevier, Amsterdam, The Netherlands,
2005, Chapter 7, GC-MS. II : Applications for pesticide analysis in food,p. 339-368.
16. Ionara R. Pizzutti 1 , André de Kok 2 , Renato Zanella 1* , Martha B. Adaime 1 , Maurice Hiemstra 2 , Cristine
Wickert 1 and Osmar D. Prestes 1 , Method validation for the analysis of 169 pesticides in soya grain, without
clean up, by liquid chromatography-tandem mass spectrometry using positive and negative electrospray
ionization,
J. Chromatogr. A, (2007) in press.