灰化酸溶-电感耦合等离子体质谱法测定煤炭中的镓锗铟

唐碧玉; 施意华; 杨仲平; 邱丽; 古行乾; 彭光菊

doi:10.15898/j.cnki.11-2131/td.201711250186

灰化酸溶-电感耦合等离子体质谱法测定煤炭中的镓锗铟

Determination of Gallium, Germanium and Indium in Coal by Inductively Coupled Plasma-Mass Spectrometry with Ashing Acid Digestion

摘要

摘要: 准确测定煤炭中的镓、锗和铟为煤炭中稀散元素的地球化学勘查提供了重要依据，对稀散金属的综合利用具有重要的经济意义。采用现有的分析方法处理煤炭样品时，由于镓、锗和铟灰化温度不同，而锗的灰化条件严格，测定结果受灰化温度影响大，因此三元素不能同时进行前处理和测定。本文通过试验优化了煤炭中镓、锗、铟的最佳灰化温度为625℃；采用硝酸-硫酸-氢氟酸溶解灰分，8 mol/L硝酸进行复溶，避免了锗的挥发损失；通过优化仪器工作条件和干扰实验，以¹⁰³Rh为内标元素，选择⁷¹Ga、⁷⁴Ge和¹¹⁵In作为测定同位素，消除了各元素的干扰，建立了电感耦合等离子体质谱法同时测定煤炭中镓、锗和铟的分析方法。结果表明：镓、锗和铟的标准曲线线性相关系数均在0.9999以上，三元素检出限分别为0.004、0.003、0.002 μg/L，精密度为1.17%~3.15%，加标回收率为96.6%~102.0%。应用本方法分析标准物质GBW07363、GBW07457和GBW07428的测定值与认定值相符。与传统的分光光度法和原子吸收光谱法比较，本方法操作更为简便快速，具有更低的测定下限，并且可以多元素同时测定。

Abstract:
BACKGROUNDThe accurate determination of gallium, germanium and indium in coal provides an important basis for geochemical exploration of the scattered elements in coal, and is of great economic significance for the comprehensive utilization of the scattered metals. The ashing conditions of germanium are strict, and the analytical results of germanium are greatly influenced by the ashing temperature. Due to the different ashing temperatures of gallium (Ga), germanium (Ge) and indium (In), the three elements could not be processed and determined simultaneously using existing analytical methods.
OBJECTIVESTo develop a method for the analysis of Ga, Ge and In simultaneously, avoid the loss of Ge in the ashing and digestion processes, and to eliminate the interference in determination.
METHODSA sensitive and efficient analysis method of ashing acid digestion method combined with Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) for determining Ga, Ge and In in coal was established by using the optimum ashing temperature of 625℃, selecting suitable acid solution conditions and mass spectrometry determining conditions. Using nitric acid-sulfuric acid-hydrofluoric acid to dissolve ash and 8 mol/L nitric acid for reconstitution, the volatilization loss of niobium was avoided. By optimizing the instrumental working conditions and interference experiments, ¹⁰³Rh was used as the internal standard element, and ⁷¹Ga, ⁷⁴Ge and ¹¹⁵In were selected as the determined isotopes, eliminating the interference of various elements.
RESULTSThe linear correlation coefficients of the standard curves of Ga, Ge and In are all above 0.9999. The detection limits of Ga, Ge and In are 0.004, 0.003 and 0.002 μg/L, respectively. The precisions range from 1.17% to 3.15%, and the sample recoveries are from 96.6% to 102.0%. The determination results of GBW07363, GBW07457 and GBW07428 are in agreement with the certified values.
CONCLUSIONSCompared to traditional analytical methods of Ga, Ge and In in coal, the proposed method is simpler, faster, and has a lower detection limit with simultaneous determination of multiple elements.

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