[Simultaneous determination of platinum (IV) and palladium (II) using spectrophotometry method].

The N-(m-methylphenyl)-N'-(sodium p-aminobenzenesulfonate)-thiourea (MMPT) was good reagent of water solubility. In the medium of an HAc-NaAc buffer solution and hexadecyltrimethylammonium bromide (CTMAB), MMPT can react with platinum (IV) and palladium (II) to form green and brown soluble complex. The maximum absorbance of the complex was at lambdaPt(max) = 754.4 nm and lambdaPD(max) = 304.6 nm. Beer's law was obeyed with the concentration in the range of 0-32.0 microg Pt(IV)/25 mL and 0-25.0 microg Pd(II)/25 mL for platinum (IV) and palladium(II) respectively. The correlated coefficient was r754.4 = 0.999 5 for platinum (IV); and r304.6 = 0.999 9 for palladium (II). Their molar absorption coefficients were epsilonPT(754.4 = 8.6 x 10(4) L x mol(-1) x cm(-1) and epsilonPd(304.6) = 7.4 x 10(4) L x mol(-1) x cm(-1) respectively. The contents of platinum (IV) and palladium (II) were converted by determination of the absorbency of mix solution of platinum (IV) and palladium (II) at 754.4 and 304.6 nm. Only Cu2+ and Co2+ interfered with the determination of palladium (II) among 50 coexistent ions, so the selectivity was good. It can be used for the determination of content of synthesis samples. The relative standard deviation (RSD) was less than 2.0%, and the recovery (%) was in the range of 96%-104%. The results are satisfactory. Because the reagent reacts with platinum (IV) and palladium (II) to form water soluble complex and does not require pre-separation for simultaneous determination of platinum (IV) and palladium (II), the method is easy to operate, rapid and environment-friendly.