Exploring the Influence of Chloridion Concentration on the Determination of Thallium by Graphite Furnace Atomic Absorption Method
The determination of thallium in soil samples by graphite furnace atomic absorption spectrometry(GFAA)was mainly disturbed by chloride ions.In order to accurately determine the content of thallium in soil samples,the absorption curves of several common matrix modifiers(NH4 NO3,Pd(NO3)2,Mg(NO3)2,NH4 H2 PO4,Ascorbic acid)to the standard solution for determination of thallium containing chlorine were investigated,and the effects of different matrix modifiers were obtained.Using soil samples as the reached object,the addition of Pd(NO3)2-Ascorbic acid in the determination of thallium was optimized.The results showed that the presence of chloride ions will negatively interfere with the determination of thalli-um,and the addition of 20%Pd(NO3)2-Ascorbic acid(0.02%～3%)composite matrix modifier showed a better inhibition effect on chloride ion interference.Under the experimental conditions,the concentration of thallium in soil certified reference materials was measured,and the results were all within the standard value range.The relative standard deviations(RSD)of 6 parallel measurements ranged from 2.8%to 9.2%,indicating that atomic absorption method had good precision and accuracy.
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