Determination of rhodium in platinum-rhodium series alloy by microwave digestion-inductively coupled plasma atomic emission spectrometry

An analysis method for the determination of rhodium in platinum-rhodium series alloy by inductively coupled plasma atomic emission spectrometry (ICP-AES) after microwave digestion was proposed. The microwave digestion conditions of sample, interference of matrix and spectral line were investigated. The results showed that the sample could be fully dissolved in a mixed acid of hydrochloric acid, hydrogen peroxide, nitric acid and hydrofluoric acid by microwave digestion twice for 60 min in closed container at 230℃. During determination of the digestion solution by ICP-AES, the interference of matrix and spectrum could be avoided by selecting proper analytical lines. The proposed method was applied to the determination of platinum-rhodium alloy simulation sample with relative error in the range of 0.10 %-0.30 % and relative standard deviation below 0.66 % (n=6),in addition the determination results were consistent with those obtained by industrial standard method. This method was applicable for the determination of rhodium in platinum-rhodium series alloy.