Spectrophotometric determination of Fe(II) in pharmaceutical multivitamin preparations by azo-dye derivatives of heteroazopyrocatechine

The authors propose 2-(3,4-dihydroxyphenylazo-1)-benzimidazole (BIAP); 3-mercapto-5-2-(3,4-dihydroxyphenylazo-)-1,2,4-triazole (METRIAP) and 2-carboxymethanotio-5-(3,4-dihydroxyphenylazo-1)-1,3,4-tiadiazole (TIDAP-SO) for spectrophotometric determination of trace amounts of Fe(II) in the presence of microamounts of other elements [Ca(II), Cu(II), Mn(II), Zn(II), Mg(II), Mo(III), P(V), S(VI)] without removing or sequestering them, and vitamins in pharmaceutical multivitamin preparations: Supradyn® and Vitapil®. The obtained results were statistically analysed and compared with those of atomic absorption spectrophotometry (AAS). The advantage of the proposed method is good selectivity, precision and reproducibility of results.