Headspace single-drop microextraction of common pesticide contaminants in honey-method development and comparison with other extraction methods

Abstract

In the present study the main factors that may influence the headspace single-drop microextraction (HS-SDME) of common pesticide contaminants (diazinon, lindane, chlorpyrifos ethyl, p,p'-DDE, and endosulfan) that may occur in honey were determined and an analytical protocol was further developed by the use of a multivariate optimization. The HS-SDME analytical method developed and two more analytical protocols for the determination of pesticides in honey: (i) by direct SDME (D-SDME), and (ii) by liquid-liquid extraction (LLE), were further validated for the determination of target analytes. The three methods were also applied in the same real honey samples and results were further discussed. By D-SDME, LODs ranged from 0.04 mu g kg(-1) for beta-endosulfan to 2.40 mg mu g kg(-1) for diazinon and repeatability expressed as %RSD from 3 for lindane to 15 for diazinon and chlorpyrifos methyl; by HS-SDME, LODs ranged from 0.07 mu g kg(-1) for p,p'-DDE to 12.54 mu g kg(-1) for chlorpyrifos methyl and repeatability expressed as % RSD from 11 for chlorpyrifos methyl to 19 for p,p'-DDE; by LLE, LODs ranged from 0.09 mu g kg(-1) for beta-endosulfan to 19.31 mu g kg(-1) for diazinon and repeatability expressed as % RSD from 6 for p,p'-DDE to 11 for lindane. For all target pesticides but p,p'-DDE that could not be recovered by D-SDME method tested. The proposed HS-SDME optimized in this study was shown to be the method of choice for the determination of diazinon in honey whereas the most favourable analytical characteristics from the comparative study performed were achieved by D-SDME.