INHIBITION OF THE SYSTEM LUMINOL-H2O2-FE(CN)(6)(3-) CHEMILUMINESCENCEBY THE MN(II) INDIRECT DETERMINATION OF ISONIAZID IN A PHARMACEUTICALFORMULATION

A flow injection procedure for the indirect chemiluminescent determina tion of isoniazid is proposed. The method is performed in a flow-injec tion manifold provided with a solid-phase reactor. The reactor was mad e from manganese dioxide physically entrapped by polymerization; the r edox reaction isoniazid manganese dioxide released Mn(II) which was mo nitored through its inhibitory effect on the reaction between luminol and hydrogen peroxide in presence of potassium hexacyanoferrate(III). The procedure resulted in a linear calibration graph over the range 5- 15 mg/L of isoniazid with a sample throughput of 43 samples/h. The inf luence of foreign compounds was studied and the method was applied to determination of the drug in a pharmaceutical formulation. (C) 1998 Jo hn Wiley & Sons, Ltd.