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采用电聚合方法在玻碳电极上制备了Keggin型磷钨酸-多壁碳纳米管-聚吡咯（PW12-MWCNT—PPy）复合物膜修饰电极，并探讨了该电极对NO2的电催化还原和电化学行为。实验结果表明，该电极对NO2-响应速度快，检测灵敏度高。NO2在2．1μmol·L^-1～1．3mmol·L^-1浓度范围内，与修饰电极上的稳态安培响应电流呈线性关系，检测限为0．62μmol-L^-1（S／N=3）．该修饰电极用于腌菜中亚硝酸根离子的测定，回收率在95％～99％之间。“,”A polyoxometalate （PW12） and MWCNT doped polypyrrole （PPy） modified electrode was prepared by electrochemical polymerization in aqueous 0.5 mol . L-1 H2SO4 solution. During the polymerization of PPy, PW12 acted as both catalyst and dopant, CNTs suggested that they had the abihty to promote electron transfer reaction. The electrochemical behavior of nitrite （ NO2 - ） at the PW12 - MWCNT - PPy modified electrode was investigated including pH effect, scan rate and so on. It showed a catalytic effect toward nitrite. The linear range of determination of NO2 - on this electrode was 2.1 μmol .L -1 to 1. 3 mmol .L-1, with a detection limit of 0.62 μmol . L-1. The developed method has been applied to the determination of NO2 - in pickled foods samples.