萃取富集-火焰原子吸收光谱法测定食品中痕量银

摘要

建立了萃取富集-火焰原子吸收法测定食品中痕量银的新方法.在硫氰酸钾、十六烷基三甲基溴化铵和氯化钠溶液体系中,银离子能被定量萃取到乙酸乙酯中,从而起到富集作用,取乙酸乙酯于火焰原子吸收光谱仪测定其中的银元素含量,提高了测定灵敏度和选择性.结果显示:银在0-200ng/mL内线性良好,r=0.999 3,测定银的灵敏度(特征浓度)为5.30×10-3μg·mL-1/1%,检出限为1.37 ng/mL,相对标准偏差为1.3%～3.5%(n=10).其中的常见离子对银测定不产生干扰,方法的加标回收率为91.0%～104.0%.%A new method for determination of trace silver in food by extraction - flame atomic absorption spectrometry was de-veloped. The silver was extracted by using ethyl acetate as extraction agent in potassium rhodanate - hexadecyl trimethyl ammonium bromide - sodium chloride solution system, and the organic phase was injected in FAAS. The sensitivity and selectivity of determination of silver was improved. The linear range was 0 - 200 ng/mL, the linear coefficient was 0. 999 3. The sensitivity was 5. 30 × 10 -3 μg · mL-1/l% , and the detection limit was 1. 37 ng/mL. The relative standard deviation was 1.3% -3. 5% (n = 10) . Most coexist-ent elements did not interfere with the determination of silver. The recovery was 91. 0% - 104. 0% .