Modified mesoporous silica materials for on-line separation and preconcentration of hexavalent chromium using a microcolumn coupled with flame atomic absorption spectrometry

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• 作者：Zheng Wang^a ; ^{wangzheng@mail.sic.ac.cn} ; Dong-Mei Fang^a ; ^b ; Qing Li^a ; ^b ; Ling-Xia Zhang^a ; Rong Qian^a ; Yan Zhu^a ; Hai-Yun Qu^a ; Yi-Ping Du^b
• 关键词：Modified mesoporous silica ; Hexavalent chromium ; Trivalent chromium ; Solid phase extraction ; Flame atomic absorption spectrometry
• 刊名：Analytica Chimica Acta
• 出版年：2012
• 期刊代码：2_00032670
• 类别：ch
• 出版时间：6 May, 2012
• 卷：725
• 期：Complete
• 页码：81-86
• 文件大小：646 K

摘要

A modified SBA-15 mesoporous silica material NH₂-SBA-15 was synthesized successfully by grafting 纬-aminopropyl-triethoxysilane. The material was characterized using transmission electron microscopy (TEM) and Fourier transform infrared/Raman (FT-IR/Raman) spectroscopy, and used for the first time in a flow injection on-line solid phase extraction (SPE) coupled with flame atomic absorption spectrometry (FAAS) to detect trace Cr (VI). Effective sorption of Cr (VI) was achieved at pH 2.0 with no interference from Cr (III) and other ions and 0.5 mol L^鈭? NH₃路H₂O solution was found optimal for the complete elution of Cr (VI). An enrichment factor of 44 and was achieved under optimized experimental conditions at a sample loading of 2.0 mL min^鈭? sample loading (300 s) and an elution flow rate of 2.0 mL min^鈭? (24 s). The precision of the 11 replicate Cr (VI) measurements was 2.1%at the 100 渭g L^鈭? level with a detection limit of 0.2 渭g L^鈭? (3 s, n = 10) using the FAAS. The developed method was successfully applied to trace chromium determination in waste water. The accuracy was validated using a certified reference material of riverine water (GBW08607).