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The rate of degradation of kresoxim methyl and its effect on soil extra-cellular (acid phosphatase, alkaline phosphatase and β-glucosidase) and intra-cellular (dehydrogenase) enzymes were explored in four different soils of India. In all the tested soils, the degradation rate was faster at the beginning, which slowed down with time indicating a non-linear pattern of degradation. Rate of degradation in black soil was fastest followed by saline, brown and red soils, respectively and followed 1st or 1st + 1st order kinetics with half-life ranging between 1–6 days for natural soil and 1–19 days for sterile soils. The rate of degradation in natural against sterilized soils suggests that microbial degradation might be the major pathway of residue dissipation. Although small changes in enzyme activities were observed, kresoxim methyl did not have any significant deleterious effect on the enzymatic activity of the various test soils in long run. Simple correlation studies between degradation percentage and individual enzyme activities did not establish any significant relationships. The pattern and change of enzyme activity was primarily due to the effect of the incubation period rather than the effect of kresoxim methyl itself. [ABSTRACT FROM AUTHOR]

The article analyzes the degradation kinetics and safety evaluation of residues of buprofezin in grapes and three types of soils of India. It aims at assessing the preharvest interval (PHI) of buprofezin to reduce its residues in grapes and ensure consumer safety. In the study, it was observed that PHI produced the desired result by minimizing buprofezin residues in grapes. As stated, this conclusion can be beneficial to the domestic and export grape industry in India as it complies with the standards of international trade.

The article presents a study about the degradation kinetics and safety evaluation of tetraconazole and difenoconazole residues in grapes. It explores the fungicides' proven bioefficacy against grapevine powdery mildew disease. The authors examined the residue dynamics of two compounds in grapes and the preharvest intervals that correspond to the multiple field applications. They recommended double rates in critical use pattern in Indian viticulture. Residue analysis method was confirmed and tested for trace-level determination of the compounds.

Rates of degradation of λ-cyhalothrin and methomyl residues in grape are reported. The dissipation behavior of both insecticides followed first-order rate kinetics with similar patterns at standard and double-dose applications. Residues of λ-cyhalothrin were lost with pre-harvest intervals (PHI) of 12.0–12.5 and 15.0–15.5 days, corresponding to the applications at 25 and 50  g a.i. ha -1 , respectively. In the case of methomyl, residues were lost with PHI of 55.0 and 61.0 days, following applications at 1 and 2  kg a.i. ha -1 , respectively. The PHI, recommended on the basis of the experimental results, was shown to be effective in minimizing residue load of these insecticides below their maximum residue limits (MRLs) in vineyard samples. [ABSTRACT FROM AUTHOR]

Highlights: [•] Dissipation kinetics of the residues of CPPU, 6-BA, GA3 and Ethephon in grape are reported. [•] Dissipation of residues followed 1st +1st order kinetics. [•] Initial residue of GA3 was below MRL and hence no pre-harvest interval (PHI) is applicable. [•] CPPU, 6-BA and Ethephon residues dissipated with PHIs of 33.5, 12 and 32days, respectively. [Copyright &y& Elsevier]

Abstract: A single quadrupole GC–MS method was optimized for multiresidue determination of 47 pesticides in grapes with limit of quantifications of each compound in compliance with the EU-MRL requirements. Sample preparation involved extraction of 10g sample with 10ml ethyl acetate (+10g sodium sulphate) by homogenization at 15,000rpm followed by centrifugation at 3000rpm. The supernatant was cleaned by dispersive solid phase extraction with primary secondary amine and acidified with 0.1% formic acid. Residues were estimated in selected ion monitoring mode with programmable temperature vaporizer-large volume injection (8μl). All the GC and MS parameters were thoroughly optimized to achieve satisfactory linearity (R 2 >0.99) within 0.01–0.25mgkg−1 with minimum matrix interferences. Recoveries at 0.01 and 0.02mgkg−1 were within 67–120% with associated precision RSD below 19%. The method was successfully applied for analysis of the real world samples for incurred residues. [Copyright &y& Elsevier]

Abstract: Food safety aspects of buprofezin, dimethoate and imidacloprid residues in pomegranate are reported. The residue analysis involved extraction of samples (15g) with 10ml ethyl acetate, cleanup by dispersive solid phase extraction with 25mg primary secondary amine and 25mg C18 sorbents and estimation by LC–MS/MS. The limit of quantification of each analyte was 0.001mgkg−1 with recoveries within 76–109%. The residues of buprofezin and dimethoate were confined to outer rind, which degraded to below the maximum residue limit for the European Union (EU-MRL) after 10.5 and 31.5days at standard dose and 32.0 and 44.0days at double dose. Residues of imidacloprid penetrated into the albedo and membrane, although at less than the MRL in all samples even at double dose. The dietary exposure of buprofezin and imidacloprid was safe on all sampling days; whereas samples with dimethoate appeared safe after 15 and 30days of field applications at standard and double doses, respectively. [Copyright &y& Elsevier]

Abstract: A novel method for the residue analysis of wine spoilage compound 2,4,6-trichloroanisole is reported. Wine (60ml) was extracted with 2ml toluene in presence of 24g MgSO4 and 6g NaCl. Cleanup of the toluene phase by dispersive solid phase extraction with mixture of 100mg CaCl2, 25mg primary secondary amine and 50mg MgSO4 was effective in minimising co-extractives and matrix effects. Time-of-flight and tandem mass spectrometric parameters were optimised to achieve linearity over 0.25–500ngml−1 and method detection limit 0.0083ngml−1 which is well below the odour threshold of 0.04ngml−1. Recoveries at 0.04, 0.2 and 0.8ngml−1 were within 80–110% (±8%). The method was reproducible when tested for Argentinean wines with intra-laboratory Horwitz ratios being <0.20 in white and red wines at both the laboratories of India and Argentina. The method could be successfully applied for incurred wine samples. [ABSTRACT FROM AUTHOR]