电感耦合等离子体原子发射光谱法测定地质样品中镉

样品经硝酸-氢氟酸-高氯酸混合酸溶解后,用氯化铵调节酸度,加入缓冲溶液使溶液的pH值保持在10～11,使铁、钴、镍等干扰元素沉淀,选择Cd 228.802 nm作为分析线,并设置合适的背景扣除位置,采用电感耦合等离子体原子发射光谱法(ICP-AES)测定地质样品中镉。镉的质量浓度在0.000 176~0.160 mg/L范围内与其发射强度呈线性,相关系数r=0.999 8。镉的检出限为0.06 μg/g。实验方法用于测定两个地质标准样品中镉,结果的相对标准偏差(RSD,n=12)分别为2.3%和3.2%。按照实验方法测定地质标准样品中镉,结果与认定值相符。

Determination of cadmium in geological samples by inductively coupled plasma atomic emission spectrometry

The geological sample was dissolved with mixed nitric acid-hydrofluoric acid-perchloric acid. The acidity was adjusted with ammonium chloride. The pH of solution was kept in range of 10-11 by adding buffer solution to precipitate interference elements including iron, cobalt and nickel. Cd 228.802 nm was selected as the analytical line. The proper background deduction position was set. The content of cadmium in geological sample was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The mass concentration of cadmium in range of 0.000 176-0.160 mg/L was linear to the emission intensity. The correlation coefficient was r=0.999 8. The detection limit of cadmium was 0.06 μg/g. The proposed method was applied to the determination of cadmium in two standard geological samples. The relative standard deviation (RSD, n=12) was 2.3% and 3.2%, respectively. The content of cadmium in standard geological samples was determined according to the experimental method, and the results were consistent with the certified values.