Evaluation of selected acaricides residues in honey from various phytogeographic regions of Pakistan (T-1325) (MFN 6263)

Abstract

This research work aimed to achieve highly sensitive, selective and economically feasible multi-residue technique for quantification of selected acaricides in honey by GC- μECD and GC-MSD. The two extraction procedures QuEChERS and SPE were compared and SPE was found more suitable for selected acaricides with recoveries ranged from 76% ± 1.3 - 122% ± 2.1 as recommended by SANCO. The Limits of quantification of both in-hive treated and environmentally extracted acaricides (LOQ) were lower than their MRLs which indicates that method was sufficiently sensitive. To make the clean-up process satisfactory, potential matrix effects and decrease in ion suppression/ enhancement was minimized by reducing the organic layer from 3 ml to 0.5 ml in SPE. In MSD, an enhancement of the signal was found for chlorpyrifos –methyl (ME > 200%). The Intra-day repeatability (RSDrwd) and inter-day repeatability (RSDrdd) for the selected acaricides by proposed method was observed to be lower than 16%. This was found to be within acceptable range as set by SANCO and Codex Alimentarius guidelines. The optimized chromatographic multi-residue method was practiced to assess pesticide residues in honey samples from different apiaries of Pakistan. Monitoring results indicate that 12% of the samples contained no detectable residues of the target acaricides while 88% of honey samples from different geographical regions of KP and Punjab were contaminated with at least one of selected acaricides. 6 selected acaricides residues were detected in the collected honey samples and only 5 honey samples had residues level above MRLs. In-hive treated acaricides i.e. coumaphos, t-fluvalinate and malathion were not detected in honey samples from any selected area while fipronil and mirex were detected in only two and one selected region respectively. Thus to provide safe honey to the consumers, it is essential to monitor it occasionally to eliminate the possibility of the presence of the residues of pesticides above prescribed levels.