在以0.1 mol·L-1氯化钾为支持电解质,pH为2.21的B-R缓冲溶液中辛硫磷于-0.72 V(vs.Ag/AgCl)处产生灵敏的还原峰.当辛硫磷的浓度在4×10-5~8×10-4mol·L-1范围内时,浓度与线性扫描还原峰电流呈线性关系.据此对辛硫磷样品作6次平行测定,测得平均值为3.42%,其RSD为1.7%,回收率为98.6%~103.6%.用线性扫描与循环伏安法探讨了该体系的伏安行为,结果表明,辛硫磷在玻碳电极上的电化学还原机理为不可逆过程.

In a B-R buffer solution of pH 2.21,with 0.1 mol·L-1 KCl solution as supporting electrolyte,a sensitive reductive wave of phoxim was found at the potential of -0.72 V (vs.Ag/AgCl electrode).Linear relationship between the peak current (Ip) and concentration of phoxim was obtained in the range of 4×10-5-8×10-4mol·L-1,with the scanning rate of 100 mV·s-1.In analyzing a sample of phoxim for 6 times,an average value of 3.42% was obtained with its value RSD 1.7%.Test for recovery was made by the standard addition method,and values of recovery obtained were in the range of 98.6%-103.6%.The mechanism of the electrochemical reduction of phoxim at the glassy carbon electrode was proved to be an irreversible process.