土壤试样用经盐酸-硝酸-高氯酸-氢氟酸混合酸溶解后,以活性炭吸附分离样品溶液中痕量铊,用热的草酸铵溶液进行淋洗分离,采用石墨炉原子吸收光谱法测定土壤中痕量铊。以0.06 μg·L-1氯化钯溶液作为基体改进剂,选择灰化温度、原子化温度分别为700 ℃和1 700 ℃。铊质量浓度在0.006~200 μg·L-1范围内与吸光度呈线性关系,方法检出限(3s/k)为 0.2 pg。方法用于分析土壤样品,回收率在 93.3%~106.2%之间,相对标准偏差(n=6)在0.6%~1.8%之间。

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.