韭菜上五种有机磷农药的残留监测与安全性评价

【目的】2013—2016年,在北京、天津、河北和山东采集韭菜样品,采用超高效液相色谱-三重四级杆串联质谱法检测甲胺磷、甲拌磷、甲基对硫磷、对硫磷和毒死蜱的残留量,并对其残留安全性进行评价。【方法】韭菜样品用乙腈提取,石墨碳固相萃取小柱净化,超高效反相液相色谱分离,三重四级杆质谱检测,基质匹配标准溶液的外标法定量,在添加浓度为0.01~5.0 mg/kg时,方法的准确度、灵敏度和精密度满足农药残留检测的要求。【结果】甲胺磷的最高检出浓度由70.51 mg/kg降低到0.03 mg/kg,超标率由38.10%降到2.03%;甲拌磷的最高检出浓度由6.45 mg/kg降低到0.04 mg/kg,超标率由23.81%降到1.35%;甲基对硫磷的最高检出浓度由6.62 mg/kg降低到0.13 mg/kg,超标率由25.40%降到2.70%;毒死蜱的最高检出浓度由3.95 mg/kg降低到0.47 mg/kg,超标率由15.87%降到4.73%;对硫磷的最高检出浓度由22.69mg/kg降低到0.03 mg/kg,超标率由15.08%降到1.35%。【结论】上述农药的最高残留检出浓度和超标率大幅降低,但是韭菜中仍能检出少量残留。应加强安全综合防治技术的研发,加强安全用药的宣传和指导,保障韭菜产品安全。

Pesticide residues and food safety of five organophosphorus pesticides used on Chinese chives

Objectives] To collect and analyze data on methamidophos, phorate, parathion-methyl, chlorpyrifos, and parathion residues on Chinese chives in Beijing, Tianjin, Hebei and Shandong provinces. Samples were collected from 2013 to 2016. Methods] Samples were extracted by acetonitrile, cleaned in a solid phase extraction column packed with carbon (graphite), separated by ultra-performance liquid chromatography, detected by triple quadrupole detector in multi-reaction monitoring model, and quantitatively analyzed with an external standard method by matrix-match standard solution. The method was simple and reliable which could detect these pesticide residues in Chinese chives. Results] The highest residue concentration of methamidophos decreased from 70.51 mg/kg to 0.03 mg/kg, and the over maximum residue limits (MRL) rate dropped from 38.10%to 2.03%. The highest residue concentration of phorate decreased from 6.45 mg/kg to 0.04 mg/kg and the over MRL rate dropped from 23.81%to 1.35%. The highest residue concentration of parathion-methyl decreased from 6.62 mg/kg to 0.13 mg/kg and the over MRL rate dropped from 25.40%to 2.70%.The highest residue concentration of chlorpyrifos decreased from 3.95 mg/kg to 0.47 mg/kg and the over MRL rate dropped from 15.87% to 4.73%. The highest residue concentration of parathion decreased from 22.69 mg/kg to 0.03 mg/kg and the over MRL rate dropped from 15.08%to 1.35%. Conclusion] Highest residue concentrations and over MRL ratios of five organophosphorus pesticides in Chinese chives have markedly declined over the past 3 years, but residues of these pesticides can still be detected. To ensure the safety of Chinese chives, the government should strengthen daily supervision of pesticide use, promote integrated pest management and provide better education on the reasonable use of pesticides.