Abstract: In 0. 1 mol/L NH₃-NH₄Cl buffer solution(pH9. 3), a sensitive reduction peak of es-tazolam was obtained by adsorptive voltammetry after accumulation on the surface of HMDE [initial potential -0. 80 V(w. Ag/AgCl), v=100 mV/s]. The peak potential was -1. 05 V. The linear range between ip and the concentration of estazolam is form 3. 0×10^-9to 5.0×10^-6mol/Lwith a detection limit of 1. 0×10^-9mol/L. The electrochemical behavior of the system and its electrode reaction mechanism were studied by means of cyclic voltammetry, constant-potential coulometry, etc.. The electrode reduction process is irreversible with the adsorption characteristics. The adsorption of the system obeys Frumkin adsorption isotherm. The number of reduction electrons is 2 and the transfer coefficient a is 0. 77.

Key words: Estazolam, Adsorptive wave, Adsorptive voltammetry