微型流动注射化学发光仪测定蔬菜中残留的有机磷农药

Determination of organophosphate pesticides in vegetables using mini flow-injection chemiluminescence instrument

目的利用便携式流动注射化学发光仪和紫外降解装置,检测蔬菜中残留的有机磷农药。方法过硫酸钾在紫外光的催化下能将有机磷降解为无机磷,无机磷在酸性条件下可以和钒酸盐、钼酸盐反应生成具有氧化性的磷钼钒杂多酸,可直接氧化鲁米诺产生强而稳定的化学发光信号;根据发光强度与磷的浓度在一定范围内呈线性关系,从而实现有机磷农药的定量测定。结果测定磷的检出限为1.0×10^-10g/mL,线性范围为1.0×10^-9-3.0×10^-6g/mL,对浓度为2.0×10^-7g/mL的磷平行测定11次,相对标准偏差为2.1%;当青菜中有机磷农药的添加浓度为1.00 mg/kg和2.00 mg/kg时,方法回收率在89.5%-113.5%之间。结论此方法简便快捷、准确可靠,实现了检测仪器的自动化和微型化,为市售蔬菜中有机磷农药残留的现场检测奠定了基础。

Aim To set up a flow-injection chemiluninenscence（CL） method for determination organophosphate pesticides in vegetables.Methods The degradation of organophosphate pesticides can be achieved by photo-catalysis in K2S2O8 solution.The inorganic phosphorus（the product of degradation of organophosphate pesticides）,vanadate and molybdaenate in sulfuric acid medium could form vanadomolybdophosphoric heteropoly acid,which could oxidize luminol to produce CL emission.The CL signal is linear with phosphorus concentration in a certain range.Results The CL emission intensity was correlated with the phosphorus concentration in the range 1.0×10^-9～3.0×10^-6g/mL with a detection limit of 1.0×10^-10 g/mL.The relative standard deviation（n=11） was 2.1% for 2.0×10^-7g/mL phosphorus.The recoveries ranged from 89.5 to 113.5%（by adding levels（1.00 mg/kg and 2.00 mg/kg） of 3 organophosphate pesticides）.Conclusion The method has been applied satisfactorily to the determination of organophosphate pesticides on mini chemiluminescence instrument.