石墨炉原子吸收分光光度法测定土壤中总铬

建立了土壤中总铬测定的石墨炉原子吸收分光光度法;以塞曼效应扣除背景,优化了石墨炉灰化、原子化温度、停留时间及基体改进剂用量。结果表明:当原子化温度为2 700℃,灰化温度为700℃,原子化时间2 s,灰化时间为9 s;基体改进剂用量为3~5μL时,仪器可以达到最佳工作状态。该方法铬元素浓度在0~32μg/L内呈良好的线性关系,相关系数r=0.999 9,检出限为0.3 mg/kg;对土壤标样GSS-1和ESS-1的铬测定精密度均小于5%,相对误差在-4.8%~-0.7%之间,方法的灵敏度和准确度均符合要求。因此,石墨炉原子吸收分光光度法测定土壤中总铬具有原子化温度高、干扰少、灵敏度高等特点可适用土壤中总铬的测定。

Determination of Total Chromium in Soils by Graphite Furnace Atomic Absorption Spectrometry

An analytical method of determination of total chromium in soils by use of graphite furnace atomic absorption spectrometry (GFAAS) was established in this paper. Matrix interferences were completely eliminated by deducting background with Zeeman and appropriate ashing, atomization temperature, retention time and optimum dosage determination of calcium nitrate was ooptimized in the experiment. The results showed that when the atomization temperature was 2700 C, the ashing temperature was o700 C, the atomization time was 2 s, the ashing time was 9 s, and the modified dosage of the matrix was 3~5μL, the instrument reached to the best working conditions. Under the optimal conditions, the linear range of chromium was at 0~32.0μg/L and the correlation coefficient(r) was 0.9999, with the detection limit as 0.3 mg/kg. Precision of chromium determination of the standard soil samples (GSS-1and ESS-1) was all below 5%, with relative errors between -4.8% and -0.7%. Sensitivity and precision of the method complied with the requirements. Therefore, the method was highly sensitive with high atomization temperature and less interference suitable for the determination of total chromium in soils.