FLOW INJECTION BIAMPEROMETRIC ANALYSIS OF ISONIAZID

AIM To establish a simple, rapid, and accurate electrochemical method for on-line determination of isoniazid. METHODS Based on the flow injection biamperometry for irreversible couple system, and using two preanodized platinum electrodes with the applied potential difference of 0 V, the biamperometric method for the determination of isoniazid has been proposed by coupling the catalytic oxidation of isoniazid and the reduction of platinum oxide. RESULTS Common excipients, inorganic ions, amino acids, vitamins and proteins do not interfere with the determination. Linear relationship between current and the concentration of isoniazid is obtained in the range of 1.0×10^-6 -1.0×10^-4mol·L^-1 (γ=0.998, n=11). The RSD of 1 8% was obtained for 8 successive determinations of 1.0×10^-5mol·L^-1 isoniazid. CONCLUSION The proposed method has been shown to be sensitive, selective, rapid (120 samples·h^-1), and suitable for the on-line direct determination of isoniazid.