Simultaneous Determination of Ga, Ge and In in Zinc Concentrate by Inductively Coupled Plasma Mass Spectrometry

In order to accurate and quick determination of Ga, Ge, and In in zinc concentrate samples, the title method was proposed, and the aspects of the selection of sample dissolution system, target element isotope and internal element, as well as the interference and elimination of coexisting element and reagent were discussed. After sieving the sample, the nitric acid-hydrofluoric acid-perchloric acid system was used to dissolve the sample by heating. Then 25% (volume fraction, the same below) sulfuric acid solution was added dropwise to the obtained solution, and 50% (volume fraction) nitric acid solution was added to dissolve the salt. After constant volume and filtration, the filtrate was diluted according to the content of target elements and the coexisting element Cu in the actual sample, and analyzed by inductively coupled plasma mass spectrometer. It was shown that the nitric acid-hydrofluoric acid-perchloric acid system could fully dissolve the sample, avoiding the effects of Ga and Ge volatilization loss, silicon compound inclusion, and encapsulated sulfur ball inclusion. Dropping 25% sulfuric acid solution into the test solution could avoid the formation of iron oxide precipitation from Fe in the sample. Internal standard element isotope ¹⁰³Rh was used to correct ⁷¹Ga and ⁷⁴Ge, and ¹⁸⁷Re was used to correct ¹¹⁵In, eliminating the interference caused by most coexisting elements. Further diluting the sample solution was used for eliminating the correction deviation caused by internal standard correction when the Cu mass fraction was not less than 8%. The interference of ⁷⁴Se on ⁷⁴Ge and ¹¹⁵Sn on ¹¹⁵In was corrected using online/offline formulas. Linear ranges of the standard curves of Ga, Ge, and In were in the range of 0.20-50.00 μg·L^-1, with detection limits (3s) in the range of 0.002 6-0.010 5 μg·g^-1. The proposed method was used for the analysis of reference materials and actual samples, and the determined and certified values of Ga, Ge and In in the reference materials were basically consistent, with recoveries obtained by standard addition method in the range of 95.0%-106%, and RSDs (n=11) of the determined values ranged from 2.6% to 8.2%. The proposed method was compared with literature methods, and the determined values of the 2 methods were basically consistent.