تحليل متبقيات المبيدات في العسل باستخدام طريقة استخراج خلات الإيثيل: التحقق من صحة والدراسة الاستقصائية التجريبية في عينات حقيقيةPesticide residues analysis in honey using ethyl acetate extraction method: validation and pilot survey in real samples

This paper presents a cost-effective and validated multi residue confirmatory method for the
determination of 167 chemically different pesticides and a survey study on Cyprus honey
samples. This method uses ethyl acetate for the extraction of pesticides from honey and the
determination is performed with liquid chromatography (LC) coupled to mass spectrometry
(MS) operating in tandem mode (MS/MS) and with GC–ECD (gas chromatography with
electron capture detector) analysis. The LC-MS/MS analytical system is especially important
in the analysis of polar and non-volatile pesticides. For the validation of the method, blank
honey samples were spiked with 146 pesticides (organophosphorous, carbamates, triazoles,
amides, neonicodinoids, strobilurines, phenylureas, bendimidazoles and others) for the
LC-MS/MS analysis at three levels: 0.01, 0.05 and 0.1 mg kg−1 and with 21 pesticides for
the GC-ECD analysis at two levels: 0.01 and 0.05 mg kg−1for organochlorines and 0.05 and
0.2 mg kg−1for the pyrethroids. As blank sample, a sample of honey which did not contain
detectable levels of the analytes sought was used. The validation study was in accordance to
the DG SANCO guidelines. The scope of validation included recovery, linearity, limits of
quantification and precision. Linearity is demonstrated all along the range of concentration
that was investigated with correlation coefficients ≥0.98. Recoveries of the majority of
compounds were in the 70%–120% range and were characterised by precision lower or
equal to 20%. The validated method was used for a survey of 36 samples of honey produced
in different areas of Cyprus and this is the first work on Cypriot honey samples investigating
a broad range of pesticides. Only coumaphos was detected at concentrations higher than
0.01 mg kg−1 in the 58.6% of the honey samples analysed for Coumaphos. The results were
evaluated in accordance to the provisions of the Commission Regulation (EU) No 37/2010 on
pharmacologically active substances and their classification regarding maximum residue
limits (MRLs) in foodstuffs of animal origin. The concentrations of coumaphos in all positive
samples were at levels much lower than the MRL.
Keywords: pesticides; liquid chromatography; tandem mass spectrometry; gas
chromatography; electron capture detector; honey; ethyl acetate extraction