Validation of Thin-Layer Chromatographic Methods for Pesticide Residue Analysis.
IAEA TECDOC Series No. 1462.
Summary
This TecDoc gives a comprehensive overview of the practical application of TLC in pesticide residue analysis. It includes the description of various techniques for the development of TLC plates and different modes of detection of the TLC spots. The results of the participants’ research work and interlaboratory collaboration are also summarized.
Thin layer chromatography (TLC) was widely used in the 1960s and 1970s for pesticide residue analysis, and to a lesser extent when gas-liquid chromatography (GLC) and high performance liquid chromatography (HPLC) became readily available. In recent years, there have been new developments in the quality of plate coating and in detection techniques, as well as in extraction and clean up that make it possible to apply TLC according to current international quality requirements.
The TLC methods described in this publication are intended for laboratories where irregular power supply, lack of service or limited budgets are hampering the regular use of GLC and HPLC techniques. The TLC analytical techniques allow for screening, semi-quantitative determination and confirmation of pesticide residues and other organic trace contaminants and pose minor requirements on equipment and laboratory infrastructure. Therefore, the main application is to complement other instrumental techniques of pesticide residue analysis.
A Coordinated Research Programme (CRP) was initiated for investigating the applicability of TLC detection methods to complement the instrumental techniques used in pesticide residue analysis. Two similar projects were started in 1997 and 1998. The titles of the projects were (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 eighteen countries participated in the two projects. The major tasks in the program were to adapt the methods, check the repeatability and reproducibility of Rf values and the minimum detectable quantities (MDQ), and to apply the methods for determining various pesticide residues in representative matrices. Furthermore, the methods have been extended and validated for other pesticides and commodities of interest.
The IAEA officers responsible for editing the manuscript were J. Brodesser and D.H. Byron of the Food and Environment Protection Section, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. A. Ambrus of the Centre for Plant Health and Soil Conservation in Budapest, Hungary assisted in finalizing the manuscript for publication.
