Microchip‐based CEC of nitroaromatic and nitramine explosives using silica‐based sol–gel stationary phases from methyl‐ and ethyl‐trimethoxysilane precursors

Microchip‐based CEC of nitroaromatic and nitramine explosives with UV absorbance detection is described. The stationary phase was deposited in the microchip using the sol–gel process. Unique to this work, is the exclusive use of alkylated‐trimethoxysilane precursors in the gel solution. Using alkylated precursors allows for the synthesis of a hydrophobic stationary phase in a single step. Three sol–gel formulations of increasing hydrophobicity and suitable for the separation of explosives are established from methyl‐ and ethyl‐trimethoxysilane precursors. Increasing the alkyl‐chain length improved the resolution significantly, allowing for the separation of up to seven analytes. Direct injection onto the head of the stationary phase for long injection times, results in sub‐mg/L detection limits with little effect on separation efficiency.

[1]  L. Zhang,et al.  Hybrid organic–inorganic phenyl monolithic column for capillary electrochromatography , 2005, Electrophoresis.

[2]  F. Švec,et al.  Preparation of monolithic polymers with controlled porous properties for microfluidic chip applications using photoinitiated free‐radical polymerization , 2002 .

[3]  Greg E Collins,et al.  Integrated microfluidic device for solid-phase extraction coupled to micellar electrokinetic chromatography separation. , 2005, Analytical chemistry.

[4]  W. Choi,et al.  Chip electrochromatography of polycyclic aromatic hydrocarbons on an acrylate-based UV-initiated porous polymer monolith , 2001, Fresenius' journal of analytical chemistry.

[5]  Stephen C. Jacobson,et al.  Open channel electrochromatography on a microchip , 1994 .

[6]  Soga,et al.  Performance of a monolithic silica column in a capillary under pressure-driven and electrodriven conditions , 2000, Analytical chemistry.

[7]  Steven M Cramer,et al.  On-chip electrochromatography using sol-gel immobilized stationary phase with UV absorbance detection. , 2004, Journal of chromatography. A.

[8]  A. Manz,et al.  Micellar electrokinetic chromatography separations and analyses of biological samples on a cyclic planar microstructure. , 1996, Analytical chemistry.

[9]  R. Zare,et al.  Toward sol-gel electrochromatographic separations on a chip , 2002 .

[10]  S. Hjertén,et al.  Electroosmosis- and pressure-driven chromatography in chips using continuous beds. , 2000, Analytical chemistry.

[11]  S. Terabe,et al.  Sweeping of Analyte Zones in Electrokinetic Chromatography , 1999 .

[12]  Fahima Ouchen,et al.  An integrated solid‐phase extraction system for sub‐picomolar detection , 2002, Electrophoresis.

[13]  Iulia M Lazar,et al.  Microfluidic device for capillary electrochromatography‐mass spectrometry , 2003, Electrophoresis.

[14]  J. Michael Ramsey,et al.  Integrated microchip device with electrokinetically controlled solvent mixing for isocratic and gradient elution in micellar electrokinetic chromatography , 1997 .

[15]  T. Shepodd,et al.  Reversed-phase electrochromatography of amino acids and peptides using porous polymer monoliths. , 2001, Journal of chromatography. A.

[16]  S. Terabe.  Electrokinetic chromatography: An interface between electrophoresis and chromatography , 1989 .

[17]  Haifang Li,et al.  Chiral separation of dansyl amino acids by PDMS microchip gel monolithic column electrochromatography with γ-cyclodextrin bonded in polyacrylamide , 2005 .

[18]  Xin Zhang,et al.  Allyl-functionalized hybrid silica monoliths. , 2005, Chemical communications.

[19]  S. Jacobson,et al.  Solvent-programmed microchip open-channel electrochromatography. , 1998, Analytical chemistry.

[20]  Koji Otsuka,et al.  Electrokinetic separations with micellar solutions and open-tubular capillaries , 1984 .

[21]  R. Freitag,et al.  One-Step Synthesis of Monolithic Silica Nanocomposites in Fused Silica Capillaries , 2003 .

[22]  K. Uchiyama,et al.  Cyclodextrin‐modified monolithic columns for resolving dansyl amino acid enantiomers and positional isomers by capillary electrochromatography , 2003, Electrophoresis.

[23]  Á. Végvári,et al.  A hybrid microdevice for electrophoresis and electrochromatography using UV detection , 2002, Electrophoresis.

[24]  N. Penner,et al.  Nanoliter capillary electrochromatography columns based on collocated monolithic support structures molded in poly(dimethyl siloxane) , 2001, Electrophoresis.

[25]  Z. El Rassi,et al.  Capillary electrochromatography with monolithic silica column: I. Preparation of silica monoliths having surface‐bound octadecyl moieties and their chromatographic characterization and applications to the separation of neutral and charged species , 2003, Electrophoresis.

[26]  Geometric effects of collocated monolithic support structures on separation performance in microfabricated systems , 2002 .

[27]  G. Collins,et al.  Micellar electrokinetic chromatography and capillary electrochromatography of nitroaromatic explosives in seawater , 2006, Electrophoresis.

[28]  T. Shepodd,et al.  Conduct-as-cast polymer monoliths as separation media for capillary electrochromatography. , 2001, Analytical chemistry.

[29]  Martin Pumera,et al.  Microchip-based electrochromatography: designs and applications. , 2005, Talanta.

[30]  M. Breadmore,et al.  Towards a microchip‐based chromatographic platform. Part 2: Sol‐gel phases modified with polyelectrolyte multilayers for capillary electrochromatography , 2003, Electrophoresis.

[31]  J P Landers,et al.  A universal concept for stacking neutral analytes in micellar capillary electrophoresis. , 1999, Analytical chemistry.

[32]  Z. El Rassi,et al.  Capillary electrochromatography with monolithic-silica columns. II. Preparation of amphiphilic silica monoliths having surface-bound cationic octadecyl moieties and their chromatographic characterization and application to the separation of proteins and other neutral and charged species. , 2003, The Analyst.

[33]  J. Landers,et al.  Toward optimization of macroporous silica gels for application to capillary or microchip-based CEC and LC , 2004 .

[34]  R. Oleschuk,et al.  Trapping of bead-based reagents within microfluidic systems: on-chip solid-phase extraction and electrochromatography , 2000, Analytical chemistry.

[35]  N Gottschlich,et al.  Two-dimensional electrochromatography/capillary electrophoresis on a microchip. , 2001, Analytical chemistry.

[36]  K. A. Wolfe,et al.  Towards a microchip‐based chromatographic platform. Part 1: Evaluation of sol‐gel phases for capillary electrochromatography , 2002, Electrophoresis.

[37]  L. Zhang,et al.  Hybrid organic-inorganic monolithic stationary phase for acidic compounds separation by capillary electrochromatography. , 2004, Journal of chromatography. A.

[38]  T. Shepodd,et al.  Electrochromatography in microchips: reversed-phase separation of peptides and amino acids using photopatterned rigid polymer monoliths. , 2002, Analytical chemistry.

[39]  G. Collins,et al.  Ultraviolet absorbance detection of colchicine and related alkaloids on a capillary electrophoresis microchip. , 2006, Analytica chimica acta.

[40]  R. Zare,et al.  Determination of glutamine and serine in rat cerebrospinal fluid using capillary electrochromatography with a modified photopolymerized sol-gel monolithic column. , 2003, Journal of chromatography. A.

[41]  Bailey,et al.  Separation and detection of explosives on a microchip using micellar electrokinetic chromatography and indirect laser-induced fluorescence , 2000, Analytical chemistry.

[42]  D. J. Harrison,et al.  Microchip‐based capillary electrochromatography using packed beds , 2003, Electrophoresis.

[43]  Z. El Rassi,et al.  Capillary electrochromatography with monolithic silica columns III. Preparation of hydrophilic silica monoliths having surface-bound cyano groups: chromatographic characterization and application to the separation of carbohydrates, nucleosides, nucleic acid bases and other neutral polar species. , 2004, Journal of chromatography. A.

[44]  Martin A. M. Gijs,et al.  Utilization of the sol–gel technique for the development of novel stationary phases for capillary electrochromatography on a chip , 2001 .

[45]  Edward S. Yeung,et al.  Characterization of band broadening in capillary electrophoresis due to nonuniform capillary geometries , 1994 .

[46]  Hua Xiao,et al.  Electrochromatographic evaluation of a silica monolith capillary column for separation of basic pharmaceuticals , 2005, Electrophoresis.