高灵敏度原子荧光光谱系统应用于砷、硒形态分析的研究

Study on Arsenic/Selenium Speciation Analysis by a Modified High Sensitive Atomic Fluorescence Spectrometric System

将实验室自制的高灵敏度原子荧光光谱系统与色谱分离、在线紫外光前处理装置联用，实现了元素形态的液相色谱分离、在线紫外消解、蒸气发生及原子荧光光谱测定，并以砷、硒两元素为例对系统的分析性能进行研究。样品通过加热混旋提取、离心、过滤，使用反相色谱柱并以5.0mmol／L磷酸氢二铵缓冲溶液（pH5.7）-0.5mmol／L四丁基溴化铵（TBAB）-1％甲醇为流动相进行分离；三价砷（AsO3-3）、二甲基砷（DMA）、一甲基砷（MMA）、五价砷（AsO3-4）可在7min内进行分离和测定，硒代胱氨酸（SeCys）、硒代蛋氨酸（SeMet）、四价硒（SeO2-3）、六价硒（SeO2-4）的测定约需11min。在优化实验条件下，方法检出限（DLs，S／N=3）为0.08～0.74μg/L；相对标准偏差（RSD，n=7）为1.4％～7.9％，实际样品的加标回收率为82.5％～116.596；砷、硒各形态在0.28～40.0μg/L和0.38～80.0μg/L范围内线性良好。建立的联用系统稳定性好、检出限低，可实现样品中低浓度砷、硒形态的准确测定。

A self-mode lab＇s high sensitive atomic fluorescence spectrometric detection system combined with liquid chromatography, online ultraviolet photochemical digesting and vapor generation device was established and evaluated. Arsenic and selenium species in various samples were extracted by heating-shaking and centrifugal filtration. All the analytes were separated on a reversed-phase column using mobile phase of 5.0 mmol/L phosphate buffer（pH 5.7） -0.5 mmol/L tetrabutyl ammonium bromide（TBAB）-1% methanol. The separations of AsO3-3, DMA, MMA, AsO3-4 and SeCys, SeMet, SeO2-3, SeO2-4 were achieved within 7 min and 11 min, respectively. Under the optimized operating con- ditions, the detection limits（DLs, S/N=3） were in the range of 0.08-0.74 μg/L, and the relative standard deviations （RSD, n = 7） were 1.4% - 7.9%. The standard spiked recoveries for real samples were in the range of 82.5% -116.5%. Linearities were obtained in the ranges of 0.28 -40.0 μg/L for arsenic species and 0.38 - 80.0 μg/L for selenium species. The developed system was successfully applied in the detection of low levels of arsenic and selenium species in matrices.