Application of 4-(2-Pyridylazo)resorcinol for flotation-spectrophotometric determination of iron

Abstract

Optimum conditions for flotation-spectrophotometric determination of iron with 4-(2-pyridylazo)resorcinol (PAR) based on a 1:2 FeII-PAR complex were found to be as follows: flotation solvent (chloroform), shaking time (2 min), pH (4.5±0.5), concentration of PAR (2.0×10-4 mol L-1), reducing agent (hydroxylamine hydrochloride), solvent for the floated compound (dimethylsulphoxide, DMSO), wavelength for spectrophotometric measurements (718 nm), and volumes of the organic solvents (5 mL of chloroform and 3 mL of DMSO). Calibration graphs were compared for different volumes of the aqueous phase - 10 mL and 40 mL; the corresponding linear ranges were 0.30-1.3 μg mL1 and 0.25-1.0 μg mL-1. The iron content was successfully determined in soil samples, reference standard materials (PS-1, COOMET No. 0001-1999 BG, SOD No. 310a-98; PS-2, COOMET No. 0002-1999 BG, SOD No. 311a-98; and PS-3, COOMET No. 0003-1999 BG, SOD No. 312a-98) and zinc sulfide concentrates.