针对近红外光谱技术的检出限高和金属离子在近红外区无信号响应的问题,合成了巯基聚倍半硅氧烷微球(PMPSQ),用以高效富集水溶液中的微量汞(Ⅱ)和银(Ⅰ)离子.通过金属离子与巯基官能团螯合从而获得相应的近红外信号响应,采集吸附了金属离子的PMPSQ的近红外漫反射光谱,采用偏最小二乘法建立了定量校正模型.结果表明,采用巯基微球富集结合近红外光谱技术可以同时测定水中浓度分别为0.16~1.80 mg/L的汞(Ⅱ)离子和0.15~1.70 mg/L的银(Ⅰ)离子.
A method for simultaneous determination of metal ions in water samples was developed using adsorption preconcentration and near-infrared diffuse reflectance spectroscopy(NIRDRS).A high capacity adsorbent of thiol-functionalized polysilsesquioxane microspheres(PMPSQ) was prepared for preconcentration of Hg2+ and Ag+ in aqueous solutions.After adsorbing the analytes onto the adsorbent,NIRDRS was measured and partial least squares(PLS) models were established for fast and simultaneous quantitative prediction.Because the interaction of the ions with the functional groups of the adsorbent can be revealed from the spectra,the models built with the water samples were proven efficient enough to predict Hg2+ and Ag+ in a range of 0.16—1.80 mg/L and that of 0.15—1.70 mg/L respectively.The wavenumber changes of C—H group are thought to be the quantitative basis.