聚乙烯亚胺修饰氧化石墨烯材料选择性吸附分离乌龙茶叶中无机砷的研究

Study on selective adsorption and separation of inorganic arsenic from Oolong tea by polyethyleneimine modified graphene oxide material

中文关键词:  聚乙烯亚胺  氧化石墨烯  乌龙茶叶  无机砷  选择性吸附分离

英文关键词:polyethyleneimine  graphene oxide  Oolong tea  inorganic arsenic  selective adsorption and separation

中文摘要:

      目的 将聚乙烯亚胺(polyethyleneimine, PEI)修饰于氧化石墨烯(graphene oxide, GO)表面, 制备PEI@GO合成材料以实现乌龙茶叶中无机砷的选择性吸附分离, 并结合原子荧光光谱法对其进行检测。方法 利用傅里叶红外光谱、电镜扫描、Zeta电位分析对PEI@GO进行表征, 并建立基于PEI@GO的管尖固相萃取(pipette tip solid phase extraction, PTSPE)体系结合氢化物发生-原子荧光光谱法(hydride generation atomic fluorescence spectrometry, HG-AFS)实现乌龙茶中无机砷的选择性吸附分离和准确定量。结果 傅里叶红外光谱图中出现N-H特征峰, 表明PEI成功修饰于GO的表面, 电镜下PEI@GO呈现多孔的山脊山谷结构, Zeta电位分析其等电点约为9.7, 在pH 6下, 5 mg PEI@GO对As (V)溶液吸附率达95.84%, 所建立的PTSPE-HG-AFS法最低检出限为0.027 μg/L, 相对标准偏差为0.48%, 不同品种乌龙茶样品中无机砷含量为13.00~122.00 μg/kg, 回收率在86.48%~108.98%之间。结论 制备的PEI@GO材料可有效实现无机砷的选择性吸附分离, 所建立的方法操作简便、灵敏度高, 可准确用于实际茶叶样品中无机砷的分析检测。

英文摘要:

      Objective To achieve the selective adsorption and separation of inorganic arsenic in Oolong tea though a novel material of PEI@GO prepared by modifying the polyethyleneimine (PEI) on the surface of graphene oxide (GO), and detect the inorganic arsenic by atomic fluorescence spectrometry. Methods PEI@GO was characterized by Fourier transform-infrared spectroscopy, scanning electron microscope, and Zeta potential analysis, and a PEI@GO-based pipette tip solid phase extraction (PTSPE) system combined with hydride generation atomic fluorescence spectrometry (HG-AFS) was established to realize selective adsorption separation and accurate quantification of inorganic arsenic in Oolong tea. Results The N-H characteristic peak appeared in the Fourier transform infrared spectrum, indicating that PEI was successfully modified on the surface of GO, under the electron microscope, PEI@GO showed a porous ridge-valley structure, and its isoelectric point was about 9.7 by Zeta potential analysis. At pH 6, the adsorption rate of 5 mg PEI@GO to As (V) solution reached 95.84%. The minimum limit of detection of the established PTSPE-HG-AFS method was 0.027 μg/L, and the relative standard deviation was 0.48%, the content of inorganic arsenic in different varieties of Oolong tea samples was 13.00?122.00 μg/kg, and the recoveries were 86.48%?108.98%. Conclusion The prepared PEI@GO material can effectively realize the selective adsorption and separation of inorganic arsenic. The established method is easy to operate and has high sensitivity, which can be accurately used for the analysis and detection of inorganic arsenic in actual tea samples.