Rapid screening of organophosphorus pesticides in honey and bees by liquid chromatography—Mass spectrometry

Twenty-two organophosphorus pesticide residues were simultaneously determined in honey and honeybee samples by extraction procedures based on solid-phase and liquid chromatography-atmospheric pressure chemical ionization-mass in positive and negative ionization modes. Pesticides in honeybee samples were extracted by matrix solid phase dispersion with C18 silica and subsequently eluted with a mixture of dichloromethane-methanol (85∶15, v/v). The average recoveries from spiked honeybees (0.5–10 μg g−1) ranged from 76% for coumaphos to 100% for omethoate, with relative standard deviations between 3 and 17%. Limits of detection were ≤0.13 μg g−1 and limits of quantification were ≤0.43 μg g−1. Honey samples required only dilution with water prior to solid phase extraction (SPE) with C18 silica and further elution with ethyl acetate, methanol and dichloromethane. Mean recoveries from spiked honey (0.1–5 μg g−1) were between 14% for omethoate to 102% for azinphos ethyl, with relative standard deviations ranging from 2 to 17%. Limits of detection were from 0.01 to 0.24 μg g−1 and limits of quantification from 0.03 to 0.80 μg g−1.