PESTAB. Recent developments in the application of analytical techniques to gas chromatography (GC) and high pressure liquid chromatography (HPLC) analysis of pesticides are reviewed. The most common types of techniques for derivization include esterification, alkylation, silylation, perhalogenation, and photochemical techniques. Esterification and transesterification are the two most important derivization procedures for analysis of chlorophenoxy acid herbicides (2,4-D, 2,4,5-T, dicamba, picloram, fenoprop). Methods applicable to carbamate compounds and their hydrolysis products are perhalo-acetylation and alkylation techniques. Silylation and alkylation of triazines, esterification and silylation of phenols (pentachlorophenol, PCP), pyrolytic methylation of organophosphates (parathion, temephos, chlorophoxim), and photolysis, chlorination and hydrolytic reactions in organochlorine pesticide (PCB's, DDT, PBB) derivatization are among the analytical techniques currently used in GC analysis. HPLC allows the direct analysis of certain intact pesticide molecules which previously had to be derivatized for GC analysis.