Titrimetric and Polarographic Microdetermination of Nitrite by Amplification Reactions

Department of Chemistry, College of Science, Mosul University, Mosul, Iraq

Manuscript received 5 September 1981, revised 8 March 1982, accepted 28 April 1983

Nitrite (5.2000 μg) oxidizes iodide quantitatively to iodine in acidic medium. The liberated iodine is extracted into chloroform and is reduced to iodide by back extraction with 1% sodium hydrogen sulphite solution. The iodide ion is then amplified by bromine oxidation and determined titrimetrically or polarographically by measuring the a.c. polarographic wave of the iodate formed in alkaline medium (pH 12). The coefficient of variation of the two methods does not usually exceed 2% for 2000 Ag of nitrite but increases to 3.2%, at 5 μg level.