烯酰吗啉在人参和土壤中的残留动态及膳食风险评估

采用高效液相色谱-质谱技术研究质量分数80%的烯酰吗啉水分散粒剂在人参根、茎、叶和土壤中的消解动态及最终残留量，并对其可能产生的膳食安全风险进行评估。样品经丙酮提取，GPR固相萃取柱净化后以液相色谱分离，采用电喷雾电离源，以质谱正离子扫描多反应监测模式进行定量分析，外标法定量。在0.01～0.20 mg/kg添加范围内，烯酰吗啉在人参根、茎、叶及土壤中的回收率为82.0%～95.5%，相对标准偏差为5.01%～7.67%。施药剂量为800 g a.i./hm2时，烯酰吗啉在人参根、茎、叶和土壤中的降解半衰期为9.13～16.35 d。在一个生长季节使用1 次，施药剂量为533.33～800 g a.i./hm2时，烯酰吗啉在人参根、茎、叶和土壤中的最终残留量分别为未检出～0.024 5、0.023 3～0.138 7、0.121 5～0.618 2 mg/kg和0.008 4～0.073 8 mg/kg，风险商值为3.56×10-7（远小于1），风险较低，处于安全水平。建议我国烯酰吗啉在人参中的最大残留限量值可暂定为0.05 mg/kg，安全间隔期为28 d。

Degradation Dynamics and Dietary Risk Assessment of Dimethomorph in Ginseng and Soil

A high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS-MS) was developed to determine the degradation dynamics and final residues of 80% dimethomorph water dispersible granules (DWG) in ginseng root, stem, leaf and soil, and dietary risk assessment of dimethomorph was conducted. The samples were extracted with acetone, cleaned-up with GPR solid phase extraction cartridge, separated by liquid chromatography and analyzed by electron spray ionization (ESI) in positive ion multiple reaction monitoring (MRM) mode. The quantification was performed
by the external standard method. The recoveries of dimethomorph in ginseng root, stem, leaf and soil at spiked levels of 0.01–0.20 mg/kg were in the range of 82.0%–95.5% with relative standard deviation of 5.01%–7.67%. The half-life of dimethomorph was 9.13–16.35 days at spraying dosage of 800 g a.i./hm2. The final residues were below 0.024 5 mg/kg in root, 0.023 3–0.138 7 mg/kg in stem, 0.121 5–0.618 2 mg/kg in leaf and 0.008 4–0.073 8 mg/kg in soil, and the risk was very low with a risk quotient of 3.56×10–7 (much less than 1), and the residues could be reduce to a safe level after single spraying in dosage range from 533.33 to 800 g a.i./hm2 during the growth season. The MRL of dimethomorph in ginseng is suggested to be 0.05 mg/kg temporarily, and its preharvest interval is 28 days.