Field Rapid Determination of Platinum and Palladium in Geochemical Samples by Spectrophotometry with Sulfhydryl Cotton Enrichment

For the determination of Pt and Pd in geochemical samples, traditional and modern analytical methods are based on assaying or activated carbon and resin preconcentration and determination by Spectrophotometry and Inductively Coupled Plasma-Mass Spectrometry. However, these requirements cannot be met in the field. Based on the character of samples and the applicability of Spectrophotometry, this study develops a method in rapid determination of Pt and Pd in geochemical samples in the field. Samples are decomposed in the sealed Teflon container by the mixing of hydrochloric acid, potassium chlorate, sodium chloride, and ammonium hydrogen fluoride under normal temperature and pressure. Platinum and palladium are preconcentrated by sulfhydryl cotton. Pt and Pd are determined using chloroform petroleum and ether (1:3) as the extractant, and DDO as the chromogenic agent. The adsorption capacity of sulfhydryl cotton for Pt can reach 98%, and the adsorption capacity of stannous chloride-drazine hydrate (reducing agent) for Pd can reach 99%. The detection limits of the method are 0.05 μg/g and 0.02 μg/g for Pt and Pd, respectively. The analytical values of standard materials, GBW07291, GBW07293, and GBW07341 are consistent with the respectively recommended values. The direct determination values of geological samples in the field are consistent with the results of laboratory analyses.