盐酸-氯化亚锡-氟化铵体系溶样-火焰原子吸收光谱法测定水系沉积物中的低含量黄铁矿

Determination of low-content pyrite in stream sediments by flame atomic absorption spectrometry with hydrochloric acid-stannous chloride-ammonium fluoride dissolving

建立了HCl-Sn Cl2-NH4F体系溶样,火焰原子吸收光谱法测定水系沉积物中低含量黄铁矿的分析方法,在过量Sn Cl2存在下,在HCl介质中,用NH4F能选择性地保留黄铁矿,继而使用稀HNO3溶解黄铁矿。方法检出限为0.014μg/m L,RSD（n=12）为2.1%-3.7%,加标回收率为96.0%-105.5%。方法适用于水系沉积物中低含量黄铁矿的测定。

The amount of leaching pyrite is very limited using traditional saturated bromine method. Saturated chlorine methodhas a greater acidity, and suffers from the interference of coexistingsoluble iron silicate and limonite. The reagent consumption in both methods are large, and analytic error is relatively high for the determination of low content of pyrite in stream sediments. This paper established a hydrochloric acid-stannous chloride-ammonium fluoride leaching method for determination of stream sediments with a low content ofpyrite by flame atomic absorption spectrometry. In the presence of excess stannous chloride, ammonium fluoride in hydrochloric acid medium could selectively retain pyrite, which was dissolved using dilute nitric acid. The limit of detection was 0. 014μg/mL, RSD （n = 12） was 2. 1% - 3.7%, and the recovery was 96.0% - 105.5%. This method was more convenient and faster than the traditional method, and more accurate and reliable for the determination of low contentof pyrite in stream sediments. Keywords： Stream sediments; Pyrite; Hydrochloric acid-stannous chloride-ammonium fluoride extraction; Low content;Flame atomic absorption spectrometry