Objective To establish a method for determination of bismuth concentration in soil using microwave digestion with hydrofluoric acid and aqua regia by atomic fluorescence spectrometry (AFS).
Methods We compared the pretreatment effects of nitric acid+hydrochloric acid (3:1 v/v),aqua regia,hydrogen peroxide+aqua regia (1:3 v/v),and hydrofluoric acid+aqua regia (2:1 v/v).The differences of data derived by standard curve and working curve were compared,and the influences of acid medium,reducing agent concentration,and common interfering ions on the determination of bismuth were assessed to develop optimum experiment conditions.
Results Hydrofluoric acid+aqua regia was chosen for soil digestion.The linear calibration curve for bismuth was within the range of 0.3-10.0 μg/L with correlation coefficient ≥ 0.999 9.The limit of detection was 0.1 μg/L.The recovery rate was in the range of 94.1%-109%.The relative standard deviations were 1.36%-4.93%.
Conclusion In this method,the soil samples are digested completely with less reagent.The method proves to be of high accuracy and good precision with few common interfering ions,which make it effective in the determination of bismuth concentration in soilgroup
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