Core−Shell Diamond as a Support for Solid-Phase Extraction and High-Performance Liquid Chromatography

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• 作者：Gaurav Saini ; David S. Jensen ; Landon A. Wiest ; Michael A. Vail ; Andrew Dadson ; Milton L. Lee ; V. Shutthanandan ; Matthew R. Linford
• 刊名：Analytical Chemistry
• 出版年：2010
• 出版时间：June 1, 2010
• 年：2010
• 卷：82
• 期：11
• 页码：4448-4456
• 全文大小：406K
• 年卷期：v.82,no.11(June 1, 2010)
• ISSN：1520-6882

文摘

We report the formation of core−shell diamond particles for solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) made by layer-by-layer (LbL) deposition. Their synthesis begins with the amine functionalization of microdiamond by its immersion in an aqueous solution of a primary amine-containing polymer (polyallylamine (PAAm)). The amine-terminated microdiamond is then immersed in an aqueous suspension of nanodiamond, which leads to adsorption of the nanodiamond. Alternating (self-limiting) immersions in the solutions of the amine-containing polymer and the suspension of nanodiamond are continued until the desired number of nanodiamond layers is formed around the microdiamond. Finally, the core−shell particles are cross-linked with 1,2,5,6-diepoxycyclooctane or reacted with 1,2-epoxyoctadecane. Layer-by-layer deposition of PAAm and nanodiamond is also studied on planar Si/SiO₂ surfaces, which were characterized by scanning electron microscopy (SEM), Rutherford backscattering spectrometry (RBS), and nuclear reaction analysis (NRA). Core−shell particles are characterized by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), environmental scanning electron microscopy (ESEM), and Brunauer−Emmett−Teller (BET) surface area and pore size measurements. Larger (ca. 50 μm) core−shell diamond particles have much higher surface areas and analyte loading capacities in SPE than nonporous solid diamond particles. Smaller (ca. 3 μm), normal and reversed-phase, core−shell diamond particles have been used for HPLC, with 36300 plates/m for mesitylene in a separation of benzene and alkyl benzenes and 54800 plates/m for diazinon in a similar separation of two pesticides on a C₁₈ adsorbent.