Status Report on Clean - up and Determination Procedures

Evaluations of some extraction procedures for determining pesticides 'in plant material, soils and fat have been made, Polymeric adsorbents have been used Lorextracting pesticides from waters Further investigations are described into column adsorption chromatography, gel permcation chromatography and h.p.l,c, Trends in residues analysis generally are discussed, Recent progress in design and methodology of detectors, derivativization, columns and computer processing in g.l,c. and advances in h,p,l.c. are reviewed, I, CLEAN-UP PROCEDURES A multitude of methods for the extraction and clean-up of samples, which are composed, however, of only a few fundamental operational steps in slight modifications, are now available, In recent years no basically new clean-up techniques have emerged but some advance has been made upon the methodology previously adopted, Interest has been focused mainly on the multiple residue procedures in order to simplify their mode of operation, to extend their applicability to a broader range of pesticide-substrate combinations, to check their reproducibility and to introduce automated clean-up steps for routine control, In the gas chromatographic analysis of the organophosphate and organonitrogen compoundsthe clean-up of extracts does lose its importance owing to the widespread and more specific gasliquid chromatography (GLC) with the element sensitive phosphorus and nitrogen detectors, Thus, a suitable extraction procedure combined with a partitioning step is often sufficient for plant material or water, Concerning organochlorine pesticides particular emphasis has been given to the residues in fats and fat-containing foodstuffs, most of them coming from animal origin. A rather vigorous separation from co—extractives is still required here before GLC with the relatively unspecific electron capture detector.