应用自行设计的铬(Ⅵ)在线提取、分离和电感耦合等离子体原子发射光谱法检测的全自动分析系统测定明胶胶囊中铬(Ⅵ)的含量。样品(2.0 g)用pH 8.0的磷酸盐缓冲溶液(100 mL)和无水氯化镁(0.4 g),在氩气气氛中超声提取15 min。所得提取液经过滤和脱色,调整其酸度至pH 5.0,通过交换柱吸附铬(Ⅵ)。用含1 g·L-1抗坏血酸的0.4 mol·L-1硝酸溶液将铬(Ⅵ)从交换柱上洗脱。洗脱液导入仪器进行检测。铬(Ⅵ)的质量浓度在100 μg·L-1以内与发射强度呈线性关系,方法的检出限(3s)为0.30 μg·L-1。样品测定值的相对标准偏差(n=6)在1.9%~3.6%之间,加标平均回收率为99.1%。

A self-designed automatic analytical system with in-line extraction and separation of Cr(Ⅵ) in combination with inspection by ICP-AES was applied to the determination of Cr(Ⅵ) in gelatin capsules. 2.0 g of the sample was extracted ultrasonically in an atmosphere of argon for 15 min with 100 mL of PBS of pH 8.0 and 0.4 g of anhy. MgCl2. The acidity of the extract was adjusted to pH 5.0, after filtration and de-coloration, and Cr(Ⅵ) in the solution was adsorbed on the ion exchange column, and eluted from the column with 0.4 mol·L-1 HNO3 solution (containing 1 g·L-1 of ascorbic acid). The eluate was introduced into the detection unit of the analytical system. Linear relationship between values of emission intensity and mass concentration of Cr(Ⅵ) was kept in the range within 100 μg·L-1, with detection limit (3s) of 0.30 μg·L-1. Values of RSD′s (n=6) found were ranged from 1.9% to 3.6%. Value of average recovery found by standard addition method was 99.1%.