CHEMICAL SPECIATION STUDY OF PLATINUM-GROUP ELEMENTS IN GEOLOGICAL SAMPLES BY STEPWISE DISSOLUTION AND INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

A chemical speciation study method for platinum group elements in geol ogical samples was developed, including stepwise dissolution, nickel s ulphide fire assay preconcentration and inductively coupled plasma mas s spectrometry (ICP-MS) determination. Samples were firstly separated into eight components (water-soluble phase, exchangeable phase, carbon ate phase, Fe/Ni metal phase, sulfide phase, oxide phase, silicate pha se and HF-insoluble residue) by a newly-revised selective chemical dis solution procedure. The separated components were pretreated and subje cted to nickel sulphide fire assay to preconcentrate platinuim group e lements, which were determined by ICP-MS. The chemical speciation of p latinum group elements in a Danish Cretaceous/Tertiary (K/T) boundary sample was studied as a demonstration. (C) 1998 Elsevier Science B.V. All rights reserved.