Determination of trace elements in refined gold samples by inductively coupled plasma atomic emission spectrometry

This paper presents a method for the determination of trace contents of silver, copper, iron, palladium, zinc and platinum in refined gold samples. A simultaneous inductively coupled plasma atomic emission spectrometer in the radial torch position and with a cross flow nebulizer was used for the determinations. In order to compare the different calibration strategies, two sets of calibration standards were prepared. The first set was based on matrix matched calibration standards and the second was prepared without the addition of matrix material. The detection limits for the matrix-matched calibrations were higher for some elements than those without matrix matching. In addition, the internal standardization method was applied and experiments indicated that indium was the best option as the internal standard. The obtained results for gold samples with matrix matched and matrix free calibrations were compared with the results obtained by the standard addition method. The accuracy of the methods was tested by performing a recovery test. The recoveries for the spiked sample were in the range of 90-115 %. The accuracy of the methods was also tested by analysis of a certified reference material of high purity gold AuGHP1. The best results were achieved by matrix free calibration and standard addition method using indium as the internal standard at a wavelength of 230 nm.