悬浮液进样-石墨炉原子吸收光谱法测定土壤中的微量银

Determination of trace silver in soil by suspension sampling in graphite furnace atomic absorption spectrometry

探讨了固体悬浮液进样石墨炉原子吸收光谱法(GFAAS)测定土壤中微量银的方法,对悬浮液种类及浓度的选择、稳定性考察、灰化温度、原子化温度、等分析条件进行了讨论和优化。采用0.1%琼脂溶液为悬浮剂制成土壤悬浮液,并通过自动进样器将其注入石墨炉中,磷酸二氢铵溶液作基体改进剂,石墨炉原子吸收光谱法(GFAAS)测土壤中银,避免了传统样品前处理时繁琐的消解过程和可能的样品污染与损失。条件经优化后,本法测定银的检出限为0.43pg,银的质量浓度在0~6μg·L^(-1)以内呈线性关系,相关系数0.9988,测定土壤标准样品(型号ESS-5、GSS-6、ESS-15)结果与标准值一致。

The suspension sampling method was explored to determine silver in soil by using graphite furnace atomic absorption spectrometry.Analysis conditions such as suspension agents choice,suspension solution concentrations,suspension stability,ashing temperature and atomization temperature were discussed and optimized.Agar solution of 0.1%concentration was prepared and used as the suspension,and soil sample was mixed into the solution and then automatically injected into graphite furnace.Ammonium dihydrogen phosphate was adopted as matrix modifier.Above-mentioned method can be directly used to analyze trace silver contents in soil,without chemical digestion,avoiding sample loss in digestion procedure.Under the optimized condition,this method provided a detection limit of 0.43pg,and the content of silver had a good linear relationship with the spectral intensity in the range of 0~6μg·L^(-1),and the correlation coef?cient was 0.9988.Different soil reference materials(ESS-5,GSS-6 and ESS-15)were used in this research,and the testing results were consistent with the certified values.