Analytical Research Laboratory, Department of Chemistry, Aligarh Muslim University , Aligarh, India 202 002.
ACS Appl Mater Interfaces. 2014 Aug 13;6(15):13257-65. doi: 10.1021/am5031215. Epub 2014 Jul 16.
A novel solid-phase extractant was synthesized by coupling graphene oxide (GO) on chloromethylated polystyrene through an ethylenediamine spacer unit to develop a column method for the preconcentration/separation of lead prior to its determination by flame atomic absorption spectrometry. It was characterized by Fourier transform infrared spectroscopy, far-infrared spectroscopy, thermogravimetric analysis/differential thermal analysis, scanning electron microscopy, energy-dispersive spectrometry, and transmission electron microscopy. The abundant oxygen-containing surface functional groups form a strong complex with lead, resulting in higher sorption capacity (227.92 mg g(-1)) than other nanosorbents used for sorption studies of the column method. Using the column procedure here is an alternative to the direct use of GO, which restricts irreversible aggregation of GO and its escape into the ecosystem, making it an environmentally sustainable method. The column method was optimized by varying experimental variables such as pH, flow rate for sorption/desorption, and elution condition and was observed to exhibit a high preconcentration factor (400) with a low preconcentration limit (2.5 ppb) and a high degree of tolerance for matrix ions. The accuracy of the proposed method was verified by determining the Pb content in the standard reference materials and by recovery experiments. The method showed good precision with a relative standard deviation <5%. The proposed method was successfully applied for the determination of lead in tap water, electroplating wastewater, river water, and food samples after preconcentration.
一种新型固相萃取剂通过乙二胺间隔单元偶联氧化石墨烯（GO）在氯甲基化聚苯乙烯上合成，用于火焰原子吸收光谱法测定前对铅进行预浓缩/分离。采用傅里叶变换红外光谱、远红外光谱、热重分析/差热分析、扫描电子显微镜、能谱分析和透射电子显微镜对其进行了表征。丰富的含氧表面官能团与铅形成强络合物，导致比用于吸附研究的其他纳米吸附剂具有更高的吸附容量（227.92 mg g(-1)）。使用这里的柱程序是直接使用 GO 的替代方法，这限制了 GO 的不可逆聚集及其进入生态系统的逃逸，使其成为一种环境可持续的方法。通过改变实验变量，如 pH 值、吸附/解吸流速以及洗脱条件，对柱法进行了优化，并观察到其具有高的预浓缩因子（400）、低的预浓缩限（2.5 ppb）和对基体离子的高容忍度。通过测定标准参考物质中的 Pb 含量和回收实验验证了该方法的准确性。该方法具有良好的精密度，相对标准偏差<5%。该方法在预浓缩后成功应用于自来水、电镀废水、河水和食品样品中铅的测定。
