Determination of Isoniazid by Fe(II)-2,2’-Bipyridine Spectrophotometry

Abstract

In acidic media, Fe(Ш) could be reduced to Fe(Ⅱ) by isoniazid, Fe(Ⅱ) reacts with 2,2'-bipyridine to form an orange complex with a maximum absorption wavelength of 522 nm. According to this principle, the content of isoniazid can be measured indirectly by measuring the amount of Fe(Ⅱ). A new method for the determination of isoniazid by Fe(Ⅱ)-2,2'-bipyridine spectrophotometry has been established. At the optimum conditions, the linear relationship is good between the mass concentration of isoniazid and absorbance of Fe(Ⅱ)-2,2'-bipyridine complex in the range of 0.0004000-0.002800 mg/mL. The linear regression equation is A=0.0251+138.04C(mg/mL), and the linear correlation coefficient is 0.9995. This method is used to determine the content of isoniazid in isoniazid tablets, and the results are similar to those obtained by pharmacopoeia method.