Abstract: This paper covers the construction and behaviour of a mixed binder carbon paste electrode system appropriate for the cathodic stripping voltammetric quantitation of iso-niazid. The mixed binder consisted of glycerol and liquid paraffin. At the mixed binder carbon paste electrodes in a pH 3.0 buffer solution, isoniazid showed two sensitive cathodic stripping voltammetric wave at-0. 75 V (p₁) and-0. 88 V (p₂), respectively. The p₂ can be used for the determination of trace amounts of isoniazid, the linear range of the peak current to the isoniazid concentration being from 5. 0×10^-7 to 5.0×10^-5 mol/L, and the limit of detection being 1. 0×10^-7 mol/L with a relative standard deviation of 6. 0%(n=10). The proposed method was directly used to determine the drug in blood serum without the pretreatment of blood serum.

Key words: Carbon paste electrode, Isoniazid, Stripping voltammetry