低氧低分压环境下泡塑吸附-石墨炉原子吸收光谱法测定化探样品中的痕量金

Determination of Trace Gold in Geochemical Samples by Graphite Furnace Atomic Absorption Spectrometry with Polyurethane Foam Preconcentration under Hypobaric Hypoxia Condition

摘要: 针对西藏低氧低分压环境下痕量金的测定,探讨了溶矿介质、解脱时间、吸附温度、Fe³⁺加入量等对测定结果的影响。确定了最佳测定条件,并较详细讨论了Fe³⁺在溶矿和吸附过程中的重要作用。方法检出限为0.102 ng/g,测定范围为0.24~300 ng/g,准确度(ΔlgC,n=12)为0.01~0.03,精密度(RSD,n=12)为1.61%~7.33%,很好地解决了西藏地区低氧低分压低温环境下痕量金测定的技术难题。

Abstract: In order to determine trace gold in geochemical samples by GF-AAS under hypobaric hypoxia condition in Tibetan areas, the effects of digestion solvents, adsorption temperature, desorption time and dosage of Fe³⁺on the determination were discussed. GF-AAS measurement condition was optimized and the catalytic mechanism of Fe³⁺ during sample processing and pre-concentration steps was studied in detail. The detection limit of the method for Au was 0.102 ng/g with dynamic range of 0.24~300 ng/g. The accuracy of the method was 0.01~0.03 (ΔlgC,n=12) with precision of 1.61%~7.33%RSD (n=12). The method has been applied to the determination of trace gold in geochemical samples in Tibetan with satisfactory results.