Extraction inductively coupled plasma-optical emission spectrometry (ICP-OES) determination of traces of phosphorus in tungsten

Abstract

A method for the separation and preconcentration of traces of phosphorus from tungsten was developed. Solid phase extraction of the phosphovanadomolybdate complex performed on a micro-column was applied. Phosphorus was determined by optical emission spectroscopy (OES) with inductively coupled plasma (ICP) excitation. A limit of detection of 0.4/~g/g P with respect to the solid phase is obtained. By directly coupling the extraction/elution step to the ICP instrument a detection limit of 0.06 #g/g P in W was achieved. Besides, the complexity of spectral evaluation in ICP-OES determinations of traces in spectralline-rich matrices is discussed.The determination of traces of phosphorus in highly purified tungsten and tungsten oxides is of major interest in certain fields of technology and production. It is assumed that even low concentrations of phosphorus unfavourably affect the quality of tungsten materials [1,2].An increasing demand exists for pure and ultrapure refractory metal products. To characterize these materials and to control the production process, trace and ultratrace analysis is required. Highly instrumented methods, such as high-resolution mass spectrometry techniques [2][3][4][5] or activation analysis [-6, 7] are applied for ultratrace analysis.