Solid phase extraction and spectrophotometric determination of platinum(IV) with N-(3,5-dihydroxyphenyl)N'-(4-aminobenzenesulfonate)-thiourea

Abstract

A highly sensitive, selective and rapid method for the determination of platinum(IV) based on its rapid reaction with N-(3,5-dihydroxyphenyl)-Nʹ -(4-aminobenzenesulfonate)-thiourea

(DHPABT) and the solid phase extraction of the Pt(IV)-DHPABT complex with a polymer-based C₁₈ cartridge has been developed. In 0.05 - 0.5 mol L^-1 HCl medium, DHPABT reacts with platinum(IV) to form a violet complex of a molar ratio 1:3 (platinum: DHPABT). This complex is enriched by the solid phase extraction with polymer-based C₁₈ cartridge and an

enrichment factor of 200 has been obtained. The molar absorptivity of the complex is 1.01 × 10⁵L mol^-1 cm^-1  at 760 nm, and Beer's law is obeyed in the range of 0.01-3.0 μg mL^-1. The

relative standard deviation for eleven replicate analysis of 0.01μg mL^-1 &nbsp;solution is 1.86 %. The detection limit reaches 0.02 μg/L in the original samples. This method has been applied to the determination of platinum (IV) in water and soil samples. The relative standard deviation is 3.0- 3.3%<i> </i>and the standard recoveries are in the range 88 -107%. The determined values agree with those obtained by ICP-MS method.