微波消化固相萃取光度法测定氰化渣中痕量铂的研究

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

根据对氨基苯基亚甲基若丹宁(ABR)与铂(Ⅱ)的显色反应及C18固相萃取小柱对显色络合物的固相萃取,并结合微波消化样品,建立了一种测定氰化渣中痕量铂的方法.样品用微波密闭消化,在pH 2.5的氯乙酸-氢氧化钠缓冲介质中,乳化剂OP存在下,铂与ABR生成1:2稳定络合物,该络合物被C18小柱萃取富集,用氮-氮二甲基甲酰胺(DMF)洗脱,富集倍数达50倍,洗脱液定容后用光度法测定,络合物λmax=525 nm,ε=8.48×104.铂质量浓度在0.01～2.0 mg/L内符合比尔定律,方法用于氰化渣中痕量铂的测定,相对标准偏差小于3.5%.

On the basis of the color reaction of p-aminobenzylidenerhodanine（ABR） with platinum and solid phase extraction of its colored complex with C18 cartridge, a new method for the determination of platinum in cyanide residue was established. In the medium of chloroactic acid and sodium hydroxide buffer solution at pH 2.5 and in the presence of emulsifier OP, ABR reacts with platinum（Ⅱ） to form a stable 2：1 complex which can be enriched by C18 cartridge and eluted from cartridge with DMF, then the eluant is determined by spectrophotometry at 525 nm. Beer＇s law is obeyed in the range of 0.01 - 2.0 mg/L for platinum. This method has been applied to the determination of platinum in cyanide residue and the RSD was less than 3.5%.