Determination and Dietary Risk of Clothianidin and Azoxystrobin Residues in Potatoes
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Abstract:
A method for the simultaneous determination of clothianidin and azoxystrobin residues in potatoes was established. Samples were extracted with water and acetonitrile and then cleaned using anhydrous magnesium sulfate and primary secondary amine. The supernatants were filtered through 0.22 μm filters, and the filtrate solutions were subjected to high-performance liquid chromatography-tandem mass spectrometry. Linear regression showed that extraction curves for both clothianidin and azoxystrobin were reasonably close to the standard curves within a concentration range from 0.005 to 0.5 mg/L, with a correlation coefficient higher than 0.997 2. Average recovery rate of clothianidin and azoxystrobin from potatoes spiked with different pesticide levels ranging from 91.47% to 98.13%, with relative standard deviations less than 7.63%. The limit of quantification was 0.01 mg/kg for both analytes. Supervised residue trials were carried out in 12 areas in China according to the Ministry of Agriculture Guidelines for Testing of Pesticide Residues in Crops. Granules of 2% clothianidin + azoxystrobin were applied to the furrows beside the planting spots at the recommended dosage of 900 g a.i./ha before sowing or transplanting of potatoes. Clothianidin and azoxystrobin residues in potato samples at harvest were below 0.17 mg/kg and 0.074 mg/kg, respectively. Subsequently, dietary risk assessments were carried out based on the results of field residue trials, national dietary patterns, and toxicological data. The national estimated daily intakes of clothianidin and azoxystrobin were found to be 0.271 8 mg and 2.625 1 mg, respectively. The dietary risk quotients of clothianidin and azoxystrobin in potatoes were calculated as 4.31% and 20.83%, respectively, both less than 100%. This indicates that the application of granules of 2% clothianidin + azoxystrobin under the recommended Good Agricultural Practice conditions would not pose an unacceptable risk to human health.
