GFAAS Determination of Trace Amount of Thallium in Soil After Adsorption with Activated Carbon

The soil sample was dissolved in mixed acid of HCl, HNO3, HClO4 and HF. Trace amounts of Tl in the sample solution were adsorbed and separated with activated carbon, and eluted from activated carbon with hot ammonium oxalate solution as eluant. The solution obtained was used for determination of Tl by GFAAS. A solution of 0.06 μg·L-1 palladium chloride was used as matrix modifier, and the temperatures of ashing and atomization were set at 700 ℃ and 1 700 ℃ respectively. Linear relationship between values of absorbance and mass concentration of Tl was obtained in the range of 0.006-200 μg·L-1 with detection limit (3s/k) of 0.2 pg. The proposed method was used in the analysis of soil samples, giving values of recovery and RSD (n=6) in ranges of 93.3%-106.2% and 0.6%-1.8% respectively.