Microchip capillary electrophoresis/electrochemical detection of hydrazine compounds at a cobalt phthalocyanine modified electrochemical detector

摘要

This article reports on the use of cobalt(II) phthalocyanine (CoPc)-modified carbon paste amperometric detector for monitoring hydrazine compounds following their microchip separation.The marked catalytic electrochemical properties of CoPc-modified electrode display enhanced sensitivity compared with unmodified carbon pastes at a relatively low detection potential (+0.5 V versus Ag/AgCl).Factors influencing the on-chip separation and detection processes have been optimized.Three hydrazines (hydrazine,1,1 dimethylhydrazine,and phenylhydrazine) have been separated within 130 s at a separation voltage of 1 kV using a 10 mM phosphate run buffer (pH 6.5).The detection limits obtained from using the CoPc-modified carbon paste electrodes for hydrazine and phenylhydrazine are 0.5 and 0.7 muM,respectively,with linearity over the 20-200 muM range examined.Such miniaturization and speed advantages of microchip CE are coupled to the highly sensitivity and convenient preparation of CoPc-modified carbon paste electrode.The resulting microsystem should be attractive for field monitoring of toxic hydrazine compounds in environmental applications.