Determination of cobalt, copper, iron, nickel and zinc in cemented tungsten carbides with cobalt as a binder by FAAS: Matrix effect control by multivariate technique

Abstract

A new approach for the determination of cobalt, copper, iron, nickel and zinc in cemented tungsten carbides with cobalt as a binder by flame atomic absorption spectrophotometry (FAAS) is reported. Real samples were dissolved in phosphoric, hydrochloric and nitric acid. PTFE bomb or alternatively small amounts of HF were used for the enhancement of the recovery of the elements investigated. Synthetic samples were used for interference studies. Multiple linear regression was applied for the control of matrix effects and it proved to be very effective in the search for interfering elements. Using simple acid based standards, all investigated elements could be determined sequentially in a complex matrix by using an appropriate method of calculation. The method described has been succesfully applied to real type commercial samples. Results were compared with those obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES) and X-ray fluorescence spectrometry (XRF), being in good agreement with each other and having relative standard deviations better than 5%.