IAEA-TECDOC-1462 Validation of thin-layer chromatographic methods for pesticide residue analysis Results of the coordinated research projects organized by the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture 1996–2002 July 2005 IAEA-TECDOC-1462 Validation of thin-layer chromatographic methods for pesticide residue analysis Results of the coordinated research projects organized by the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture 1996–2002 July 2005 The originating Section of this publication in the IAEA was: Food & Environmental Protection Section International Atomic Energy Agency Wagramer Strasse 5 P.O. Box 100 A-1400 Vienna, Austria VALIDATION OF THIN-LAYER CHROMATOGRAPHIC METHODS FOR PESTICIDE RESIDUE ANALYSIS IAEA, VIENNA, 2005 IAEA-TECDOC-1462 ISBN 92–0–108205–3 ISSN 1011–4289 © IAEA, 2005 Printed by the IAEA in Austria July 2005 FOREWORD Thin-layer chromatography (TLC) has a long history, but has been used only to a limited extent in pesticide residue analytical laboratories since gas liquid chromatography (GLC) and high performance liquid chromatography (HPLC) became readily available. Recent developments in the quality of plate coating and detection systems, as well as in extraction and cleanup methods have revived interest in TLC. The combination of these procedures with rigid quality control has created a niche for TLC in laboratories working in compliance with ISO 17025 or GLP. The Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture recognized the importance of testing pesticide residues, especially in countries with limited resources. A coordinated research programme (CRP) was initiated for investigating the application of TLC detection methods to complement the instrumental techniques in pesticide residue analysis. An initial technical contract provided proof of the concept and elaborated the basic procedures, including a substantial database of retention factors and minimum detectable quantities of pesticides. To satisfy the demands from the eligible laboratories, two similar projects were started in 1997 and 1998. The titles of the projects were as follows: (i) Validation of Thin-layer Chromatographic Screening Methods for Pesticide Residue Analysis; and (ii) Alternative Methods to Gas and High Performance Liquid Chromatography for Pesticide Residue Analysis in Grain. Scientists from 18 countries participated in the above noted two projects. The major tasks of this programme were to adapt the methods, check the repeatability and reproducibility of Rf values, the minimum detectable quantities (MDQ) and apply the methods for determining various pesticide residues in representative matrices. Furthermore, they have extended the methods to other pesticides and commodities of interest in their countries and validated the methods elaborated. This TECDOC includes the most important results of the CRPs. The Rf and MDQ values reported by the participating scientists are compiled in one table for facilitating the assessment of the repeatability and reproducibility of the results. Since the participants were applying the same basic methodology, described in detail in the first article, these methods are only referred to in the other papers. However, the modifications made by the participants are described in their papers. The purpose of this TECDOC is to provide the readers with comprehensive information on the application of TLC detection methods to complement the instrumental techniques in pesticide residue analysis. Further information on any specific topic may be obtained from the authors. The participants of the CRPs wish to express their thanks for the opportunity provided by the IAEA to participate in these projects. A. Ambrus of the Centre for Plant Health and Soil Conservation, Budapest, Hungary, assisted in finalizing this manuscript for publication. The IAEA officers responsible for this publication were D.H. Byron and J. Brodesser of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. EDITORIAL NOTE The papers in these proceedings are reproduced as submitted by the authors and have not undergone rigorous editorial review by the IAEA. The views expressed do not necessarily reflect those of the IAEA, the governments of the nominating Member States or the nominating organizations. The use of particular designations of countries or territories does not imply any judgement by the publisher, the IAEA, as to the legal status of such countries or territories, of their authorities and institutions or of the delimitation of their boundaries. The mention of names of specific companies or products (whether or not indicated as registered) does not imply any intention to infringe proprietary rights, nor should it be construed as an endorsement or recommendation on the part of the IAEA. The authors are responsible for having obtained the necessary permission for the IAEA to reproduce, translate or use material from sources already protected by copyrights. CONTENTS SUMMARY .............................................................................................................................1 Cost effective screening methods for pesticide residue analysis in fruits, vegetables and cereal grains ............................................................................................25 Á. Ambrus, I. Füzesi, M. Susán, D. Dobi, J. Lantos, F. Zakar, I. Korsós, J. Oláh, B.B. Beke, L. Katavics Application of TLC for confirmation and screening of pesticide residues in fruits, vegetables and cereal grains: Repeatabliltiy and reproducibility of Rf and MDQ values......................................................................................................................71 Á. Ambrus, I. Füzesi, J. Lantos, I. Korsos, M. Szathmáry, T. Hatfaludi, N. Rathor Determination of pesticide residues in cereal grains............................................................123 I. Füzesi, M. Susán A thin-layer chromatographic method for the analysis of pesticides containing haloalkyl group ............................................................................149 A. Pasha, K.K. Nayak Use of multi-residue extraction associated with TLC separation and biological detection in fruit and tomato..........................................................................153 L.G. Garvajal, R.M. Loewy, A.M. Pechen de D’Angelo Adaptation and validation of the TLC detection methods in determination of pesticide residues in grain ...................................................................161 S. Culin Comparison of thin layer and gas chromatographic methods for the determination of herbicide residues in grain and soil...............................................175 D. Liu, C. Qian Validation of thin layer chromatographic screening methods for pesticide residue analysis................................................................................................181 N. Petrashkevich Determination of organophosphorus pesticides in grain by TLC ........................................187 C. Qian, D. Liu, X. Kong Adaptation of TLC detection method for the determination of pesticide residues in grains ..........................................................................................193 O. Tiryaki, P. Aysal Thin layer chromatography as an alternative method for pesticide analysis in rice grains ......................................................................................203 L.M. Varca Thin layer and gas chromatographic study of the persistence of atrazine in tropical soils ..................................................................................................209 P.O. Yeboah, S. Lowor, C.K. Akpabli Comparison of thin layer chromatographic and gas chromatographic determination of propoxur residues in a cocoa ecosystem .............................................215 P.O. Yeboah, S. Lowor, C.K. Akpabli GLOSSARY OF TERMS AND ABBREVIATIONS .........................................................223 List of Participants ...............................................................................................................227 SUMMARY 1. INTRODUCTION As food safety is among the first priorities in many countries, there is an increasing need for the determination of pesticide residues in various food commodities. The limited resources and constraints in electric power supply limit the range and number of instruments that can be operated in a large number of laboratories. On the other hand, the reliability of the results should be similar regardless of the instrumentation of the laboratories. Consequently, alternative detection and confirmatory methods are required which can complement the analyses performed with gas and liquid chromatography, and can be used in laboratories with limited financial resources and instrumentation. Thin-layer chromatography (TLC) had been widely used in the 1960s and 1970s for pesticide residue analysis, but has been used only to a limited extent since gas–liquid chromatography (GLC) and high performance liquid chromatography (HPLC) became readily available. In recent years, there have been various developments in the quality of plate coating and in detection systems, as well as in extraction and cleanup methods, that made it possible to apply TLC according to current international quality standards [1–3] as an alternative technique for screening for known pesticide residues or for confirmation of tentatively identified compounds [4]. Coordinated research programmes were initiated to study