Spectrophotometric determination of cobalt and iron in pharmaceutical preparation using 6-methyl-2-pyridinecarboxyaldehyde 4-phenyl-3-thiosemicarbazone as chromogenic reagent

The reaction of new spectrophotometric reagent 6-methyl-2-pyridinecarboxyldehyde-4-phenyl-3-thiosemicarbazone (MPAPT) towards copper(II), nickel(II), cobalt(II), cobalt(III) cadmium(II), iron(II), bismuth(III), lead(II), mercury(II), palladium(II), platinum(IV) manganese reactions are rapid at optimized pH within 1-11 in methanol-water with molar absorptivity in the range of 0.36-4.4x10(4) L-mole(-1) cm(-1). The complexes are extractable in chloroform as metal chelates compunds. The cobalt(II) develops colour even at hydrochloric acid (0.8 M) in methanol-water and colour of iron(II) changes from yellow to green at pH 9, which is extractable in chloroform. Cobalt in large excess of iron could be determined in a mixture. The reagent has been used for the determination for cobalt and iron separately and in a mixture in pharmaceutical preparations with relative standard deviation (RSD) within 0.5-21%. The results have been compared using atomic absorption spectrometer.

M Y KHUHAWAR ,PRITAM DAS JAIPAL ,