Abstract: A post chemiluminescence (PCL) reaction was observed when isoniazid was injected into the reaction mixture of potassium ferricyanide-calcein chemiluminescence (CL) reaction system. The experimental conditions of the CL reactions were optimized. A new chemiluminesence method for the determination of isoniazid with flow injection technique was developed. The detection limit is 6×10-8g/mL, the relative standard deviation is 1.8% (2.0×10-6 g/mL isoniazid, n=11), the liner range is 2.0×10-7~1.0×10-5 g/mL. The method has been successfully applied to the determination of isoniazid in the isoniazid tablets and the results were consistent with the method in the Chinese pharmacopoeia.

Key words: post-chemiluminescence reaction, potassium ferricyanide, calcein, isoniazid