A new selective, sensitive and rapid method for the determination of trace level of antimony (III) with panisaldehyde thiocarbohydrazone (PATCH) has been developed. PATCH is proposed as new, sensitive and selective complexing reagent for the extractive separation and spectrophotometric determination of antimony(III) at 3.5 M HCl to form yellow coloured binary complex of molar ratio 1:1 with 10 min. of shaking, which is very well extracted in to the dichloromethane (DCM) is measured spectrophotometrically at 400 nm against reagent blank. The proposed method obeys Beer’s law 1.5–3.5 μg mL–1 of antimony(III) and optimum range of 1.5–3 μg mL–1 of the metal as evaluated from Ringbom’s plot. The molar absorptivity and Sandell’s selectivity of antimony(III)-panisaldehyde thiocarbohydrazone complex in DCM are 2.3278 ´ 104 mol–1 cm–1 and, 0.5235 μg cm–2, respectively. The influence of various factors such as acidity, solvent, PATCH concentration on the degree of complexation has been established. A number of foreign ions are tested for their interference and use of suitable masking agent where necessary are tabulated which show that selectivity of the method has been enhanced. The method is applied for the determination of antimony(III) in binary, synthetic mixtures, ores, alloys, thin film and environmental samples.
