Liquid chromatography coupled to tandem mass spectrometry alongside gas chromatography tandem mass spectrometry has been used to analyze 200 pesticides and pesticide metabolites in honeybees.
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Liquid chromatography coupled to tandem mass spectrometry (LC–MS–MS) alongside gas chromatography tandem mass spectrometry (GC–MS–MS) has been used to analyze 200 pesticides and pesticide metabolites in honeybees.1
There has been a global decline in honeybee numbers in recent years. This phenomenon is known as colony collapse disorder (CCD). In Europe, data from the EPILOBEE project has shown that yearly colony mortality rates reported between 2012 and 2014 reached 36%.2 In the USA annual colony losses reported by beekeepers peaked at 45%.3 Pesticides are widely used as plant protection products (PPPs) in agriculture. In Poland, there are more than 1500 PPPs authorized to use, which will contain at least one of 200 different pesticides - all diverse in terms of chemical structure and toxic effects on bees.
The study team aimed to develop and validate an analytical method for the determination of possible pesticides currently approved to use within the European Union and their metabolites in honeybee samples. Two sources of exposure needed to be taken into account: pesticides used in agriculture as PPPs, and pesticides intentionally introduced into hives by beekeepers as acaricides to control the Varroa destructor mite, an external parasitic mite that attacks honeybees.
Sample preparation was based on a buffered QuEChERS method. Samples of bees were extracted with acetonitrile containing 1% acetic acid and cleaned using dispersive solid-phase extraction (dSPE). The majority of pesticides, including neonicotionoids and their metabolites, were analyzed by LC–MS–MS but some pesticides, such as pyrethroid insecticides, were analyzed by GC–MS–MS. The procedure was validated according to the Guidance document SANCO/12571/2013 at four concentration levels: 1 ng/g, 5 ng/g, 10 ng/g, and 100 ng/g bees and verified in the international proficiency test. The method was used to investigate more than 70 honeybee poisoning incidents. The analysis of bee samples spiked at the limit of quantification (LOQ) showed about 98% mean recovery value and 97% of analytes showed recovery in the required range of 70–120% and RSDr (precision) below 20%. The LOQs of pesticides were in the range of 1–100 ng/g.
This QuEChERS-based method allowed sensitive and reliable simultaneous analysis of 200 pesticides and pesticide metabolites in honeybees, which, according to the authors, makes this an important tool for establishing which pesticides could have a negative impact on bee health. - K.M.