Dissipation of sixteen pesticide residues from various applications of commercial formulations on strawberry and their risk assessment under greenhouse conditions.

Twelve commercial pesticide formulations containing sixteen active ingredients were applied on greenhouse strawberries at recommended and double doses. The dynamics and dietary risk analysis were investigated. A modified QuEChERS method based on the use of multi-walled carbon nanotubes (MWCNTs) as adsorbent followed by LC-MS/MS and GC-MS/MS detection was utilized for sample analysis. The half-lives of studied pesticides were 4.6-12.6 days and 3.8-15.8 days from two application doses. Dietary levels from the residue concentrations of the individual pesticides at harvest was contrasted with the acceptable daily intake (ADI) and acute reference dose (ARfD). The dietary risk assessment adopt the risk quotient (RQ) for chronic risk and risk probability (RP) for long-term dietary intake risk, respectively. The dietary risk induced by the studied pesticide residues in strawberry was acceptable for consumers except the pesticide fumigants. The pesticide residues at different pre-harvest intervals (PHIs) under greenhouse conditions were compared with the established maximum residue limits (MRLs). To reduce the residue levels and potential safety risk, a longer PHI or reduced application rates should be conducted.

Residue levels of five grain-storage-use insecticides during the production process of sorghum distilled spirits.

Residue levels of dichlorvos, fenitrothion, pirimiphos-methyl, malathion and deltamethrin during sorghum distilled spirits production were examined. The analytical method for these pesticides in sorghum, fermented sorghum, rice hull and distilled spirits was validated through linearity, matrix effect, accuracy and precision, limit of quantification (LOQ) and limit of detection (LOD) parameters. The pesticide residue levels before/after each process of soaking, steaming, fermentation, and distillation were determined by gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). Results showed that soaking process could obviously reduce dichlorvos residue with 87% decrease as its high vapor pressure. The steaming process reduced pesticide residues by 42-83% mainly due to evaporation or thermal degradation. Also, the fermentation could remove pesticide residues by 40-63% in favor of biological degradation. Moreover, the distillation process was proved to be effective for decreasing the pesticide residues in distilled spirits with the processing factors lower than other processes for each pesticide.