Electrochemiluminescence of the bentonite modified carbon paste electrode and its analytical application

In this paper, it was found that the isoniazide could be effectively preconcentrated onto the carbon paste electrodes doped with bentonite. Then, based on the medium exchange and its sensitizing effect of isoniazide for the weak ECL signal of electrooxidation luminol, the isoniazide could be sensitively and selectively detected with ECL method. In addition, it was also found that the blank ECL signal of electrooxid ation luminol itself, compared to the unmodified CPE, was effectively decreased on the surface of bentonite modified CPE. In this case, a more higher ratio of the ECL signal to the noise for detecting isoniazide with this chemically modified CPE was obtained. Based on these findings,, a more sensitive and selective ECL method for the determination of isoniazide was developed. At the same time, a new concept to improve the sensitivity of luminol ECL system, based on using chemically modified CPE, was also first developed in this paper. Under the selecting experimental conditions, the relative ECL intensity was linear with isoniazide concentration in the range of 5.0 x 10(-9) - 8.0 x 10(-7) mol/L. The correlation coefficient is 0.998 4.