Study on determination of trace platinum in cyanide residue by microwave-assisted digestion and solid phase extraction spectrophotometry

AbstrcatBased on a color reaction of 4-nitro-6-sulfophenolazorhodanine (NSPAR) with platinum and the solid phase extraction of its colored complex with C_(18) cartridge, a new method for the determination of platinum in cyanide residue was established. In a medium of pH 2.5 buffer solution and Tween-80 medium, NSPAR reacts with platinum (Ⅱ) to form a stable 2∶1 complex. The colored complex can be enriched by C_(18) cartridge and eluted from cartridge with DMF. Then the eluant was determined by spectrophotometry at 535 nm. Beer′s law is obeyed in range of 0.05～4.0 mg/50 L. This method was applied to the determination of platinum in cyanide residue with good results.