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A sensitive and accurate LC with tandem MS (MS/MS)-based method was developed and validated for the analysis of the herbicide glyphosate, its metabolite aminomethylphosphonic acid (AMPA), and glufosinate after derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) in various plant matrixes. The method also covers direct analysis of the glufosinate metabolites 3-methylphosphinicopropionic acid (3-MPPA) and N-acetyl-glufosinate (NAG). The homogenized samples were extracted with 0.1% formic acid in water–dichloromethane (50 + 50). The aqueous layer was derivatized with FMOC-Cl, cleaned through an HLB SPE cartridge, and determined by LC-MS/MS. The sample size, extraction solvent, sample-to-solvent ratio, derivatization conditions,and cleanup procedure were thoroughly optimized, the LOQs of glyphosate, glufosinate, and AMPA were 0.5 ng/g in grape, corn (leaf and seed), and cotton (leaf, seed, and oil) and 2 ng/g in soybean and tea. The LOQs of NAGand 3-MPPA were 50 ng/g in all the test matrixes, except tea and soybean, for which the LOQ was 100 ng/g. Inall cases, average recoveries were >80%. The method successfully performed the estimation of glyphosate in incurred corn and cotton leaf samples collected from supervised field trials.

The residue dynamics of plant growth regulators (PGR) forchlorfenuron (CPPU), 6-benzylaminopurine (6-BA), gibberellic acid (GA3) and ethephon in grape are presented, corresponding to their field applications at recommended and double doses. Random samples were collected from each treated and control plot at regular time intervals. The optimised sample preparation technique involves extraction of 10 g homogenised sample with 20 ml methanol (+1% formic acid) and measurement by LC-MS/MS multiple reaction monitoring, offering limit of quantification ≤0.0025 μg/g for all except ethephon with LOQ of 0.005 μg/g. The recoveries at LOQ and above were 84.8-109.5%. Residue dissipation of all the PGRs followed non-linear two-compartment first+first-order kinetics. CPPU, 6-BA and ethephon residues dissipated with preharvest intervals (PHIs) of 33.5, 12 and 32 days at recommended dose with no PHI applicable for GA3. The PHIs successfully minimised residue problems as observed from survey results of traceable field samples.

A novel method for the residue analysis of wine spoilage compound 2,4,6-trichloroanisole is reported. Wine (60 ml) was extracted with 2 ml toluene in presence of 24 g MgSO4 and 6 g NaCl. Cleanup of the toluene phase by dispersive solid phase extraction with mixture of 100 mg CaCl2, 25 mg primary secondary amine and 50 mg MgSO4 was effective in minimising co-extractives and matrix effects. Time-of-flight and tandem mass spectrometric parameters were optimised to achieve linearity over 0.25–500 ng ml1 and method detection limit 0.0083 ng ml1 which is well below the odour threshold of 0.04 ng ml1 . Recoveries at 0.04, 0.2 and 0.8 ng ml1 were within 80–110% (±8%). The method was reproducible when tested for Argentinean wines with intra-laboratory Horwitz ratios being