应用差分液相色谱/原子荧光法提高砷形态标准曲线的相关系数

Correlation Coefficient Improvement of Standard Arsenic Speciation Curves by Differential Liquid Chromatography-Atomic Fluorescence Spectroscopy

当用液相色谱-原子荧光(HPLC-AFS)分析砷形态时,如果样品中包含保留时间接近的形态,将导致色谱峰部分重叠。由于氢化物发生系统的固有缺陷,导致各砷化合物的分离度差,色谱峰变宽,甚至有色谱峰拖尾的现象,这更加加重色谱峰重叠,从而难以准确确定各砷的峰积分范围,因而各砷形态的标准曲线的相关系数不是很好,最终影响样品的准确分析。为了解决这个问题,本文提出差分液相色谱-原子荧光法,对HPLC-AFS原始数据首先进行高斯拟合,然后相邻采集点相减,差分数据包括正值和负值。然后将正值和负值差分数据进行移位并重新组合,得到的新数据与原始的HPLC-AFS数据相比,色谱分离度有了明显的改善,使得各砷形态的标准曲线的线性相关系数均大于0.99,利于实际样品的准确分析。

A novel data-processing technique was developed to significantly increase the correlation coefficients of the standard curves of arsenic speciation in the analysis of aqueous sample by high performance liquid chromatography with atomic fluorescence spectroscopy.In the newly-developed technique,first,the raw data were fitted with a Gaussian function,and then,subtraction is done for the fitted data acquired in the adjacent scans.Next,the differential data are stored in two data sets：one for the positive data,and the other for the absolute values of the negative data.Finally,the two newly formed data sets are shifted with respect to each other,and recombined into one data set.The comparison between the combined data with the original ones leads to a significant improvement of the chromatographic separation-an increased correlation coefficient of the standard arsenic speciation curves up to 99% and a much higher accuracy.