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Abstract：
The use of isotope-labeled internal standards is the most widely accepted approach to overcome the matrix effects on quantification of pesticides in food by LC/MS. We evaluated the impact of the matrix effects on quantification of six neonicotinoid pesticides, acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, and thiamethoxam, in food by using deuterated internal standards. The calibration curves for each pesticide were obtained by using matrix-free and matrix-matched calibration solutions with blank brown rice, carrot, and green onion extracts. For brown rice and carrot, the matrix effects were not observed. In contrast, the slopes of calibration curves for each pesticide were influenced by presence of green onion extracts in calibration solutions (variability of the slopes was 4-9%), because the ratios of peak area for native pesticide to those for internal standards were influenced by matrix. The spike-and-recovery test with green onion was also performed. The analytical values obtained by using matrix-free calibration solution were biased from the spiked concentration, whereas those obtained by using matrix-matched calibration solution were comparable to the spiked concentration. These results indicate that matrix-matched calibration solution should be used for accurate quantification of neonicotinoid pesticides in food by LC/MS using deuterated internal standards.
摘要：
使用同位素标记的内标是克服LC/MS对食品中农药定量的基质影响的最广泛接受的方法。我们评估了基质效应对六种新烟碱类农药定量的影响，啶虫脒,clothianidin,dinotfuran,吡虫啉,噻虫啉,和噻虫嗪,在食品中使用氘代内标。每种农药的校准曲线是通过使用无基质和基质匹配的校准溶液与空白糙米，胡萝卜,和葱提取物.对于糙米和胡萝卜，未观察到基质效应。相比之下,每种农药的校准曲线的斜率受校准溶液中大葱提取物的存在影响（斜率的变异性为4-9％），因为天然农药的峰面积与内标的峰面积之比受到基质的影响。还进行了用葱进行的加穗和恢复试验。使用无基质校准溶液获得的分析值与加标浓度有偏差，而通过使用基质匹配的校准溶液获得的那些与加标浓度相当。这些结果表明，应使用基质匹配的校准溶液通过使用氘代内标的LC/MS准确定量食品中的新烟碱类农药。
