Novel variable volume injector for performing sample introduction in a miniaturised isotachophoresis device.

A microdevice design furnished with a novel sample injector, capable of delivering variable volume samples, for miniaturised isotachophoretic separations is presented. Micromachining by direct milling was used to realise two flow channel network designs on poly(methyl methacrylate) chips. Both designs comprised a wide bore sample channel interfaced, via a short connection channel, to a narrow bore separation channel. Superior injection performance was observed with a connection channel angled at 45 degrees to the separation channel compared to a device using a channel angled at 90 degrees. Automated delivery of electrolytes to the microdevice was demonstrated with both hydrostatic pumping and syringe pumps; both gave reproducible sample injection. A range of different sampling strategies were investigated. Isotachophoretic separations of model analytes (metal ions and an anionic dye) demonstrated the potential of the device. Separations of ten metal cations were achieved in under 475 s.

[1]  Frank-Michael Matysik,et al.  A chip-based electrophoresis system with electrochemical detection and hydrodynamic injection. , 2002, Analytical chemistry.

[2]  S. Jacobson,et al.  Computer simulations of electrokinetic transport in microfabricated channel structures. , 1998, Analytical chemistry.

[3]  M. Masár,et al.  Isotachophoresis separations of enantiomers on a planar chip with coupled separation channels , 2001, Electrophoresis.

[4]  Sara J Baldock,et al.  Miniaturised isotachophoretic analysis of inorganic arsenic speciation using a planar polymer chip with integrated conductivity detection. , 2003, Journal of chromatography. A.

[5]  M. Masár,et al.  Determination of oxalate in urine by zone electrophoresis on a chip with conductivity detection , 2002, Electrophoresis.

[6]  Andreas Manz,et al.  Towards miniaturized electrophoresis and chemical analysis systems on silicon: an alternative to chemical sensors , 1993 .

[7]  Andreas Neyer,et al.  A new PMMA-microchip device for isotachophoresis with integrated conductivity detector , 2001 .

[8]  J. Michael Ramsey,et al.  Microchip Capillary Electrophoresis with an Integrated Postcolumn Reactor , 1994 .

[9]  Andreas Neyer,et al.  Comparison of different conductivity detector geometries on an isotachophoresis PMMA-microchip , 2001, Fresenius' journal of analytical chemistry.

[10]  R. Hergenröder,et al.  Determination of selenoamino acids by coupling of isotachophoresis/capillary zone electrophoresis on a PMMA microchip , 2002 .

[11]  N. Goddard,et al.  Integrated moulded polymer electrodes for performing conductivity detection on isotachophoresis microdevices. , 2003, Journal of chromatography. A.

[12]  D. Kaniansky,et al.  Direct determination of valproate in serum by zone electrophoresis–isotachophoresis on a column-coupling chip , 2003 .

[13]  Kaniansky,et al.  Capillary electrophoresis separations on a planar chip with the column-coupling configuration of the separation channels , 2000, Analytical chemistry.

[14]  R. Hergenröder,et al.  Micro-structured analytical instrumentation for the analysis of liquids☆ , 2002 .

[15]  D. J. Harrison,et al.  Micromachining a Miniaturized Capillary Electrophoresis-Based Chemical Analysis System on a Chip , 1993, Science.

[16]  R. Bodor,et al.  Isotachophoresis and isotachophoresis--zone electrophoresis separations of inorganic anions present in water samples on a planar chip with column-coupling separation channels and conductivity detection. , 2001, Journal of chromatography. A.

[17]  Qifeng Xue,et al.  Sample pre-concentration by isotachophoresis in microfluidic devices. , 2002, Journal of chromatography. A.

[18]  P. Fielden,et al.  The simultaneous separation of twenty-one metal cations using capillary isotachophoresis with on-column conductivity detection , 1999 .

[19]  Andreas Manz,et al.  High-Speed Separation of Antisense Oligonucleotides on a Micromachined Capillary Electrophoresis Device , 1994 .

[20]  J. Michael Ramsey,et al.  Effects of injection schemes and column geometry on the performance of microchip electrophoresis devices , 1994 .

[21]  Sara J Baldock,et al.  Bidirectional isotachophoresis on a planar chip with integrated conductivity detection. , 2002, The Analyst.

[22]  A Manz,et al.  Narrow sample channel injectors for capillary electrophoresis on microchips. , 2001, Analytical chemistry.

[23]  J. Rossier,et al.  Pressure pinched injection of nanolitre volumes in planar micro-analytical devices. , 2002, Lab on a chip.

[24]  R. Bodor,et al.  Determination of organic acids and inorganic anions in wine by isotachophoresis on a planar chip. , 2001, Journal of chromatography. A.

[25]  N. Goddard,et al.  Determination of the ascorbate content of photographic developer solutions using miniaturised isotachophoresis on a planar chip. , 2003, The Analyst.

[26]  J. Alarie,et al.  Electrophoretic injection bias in a microchip valving scheme , 2001, Electrophoresis.

[27]  R. Bodor,et al.  Determination of bromate in drinking water by zone electrophoresis‐isotachophoresis on a column‐coupling chip with conductivity detection , 2002, Electrophoresis.

[28]  S. Jacobson,et al.  Computer simulations of electrokinetic injection techniques in microfluidic devices , 2000, Analytical chemistry.

[29]  Q. Fang,et al.  A high-throughput continuous sample introduction interface for microfluidic chip-based capillary electrophoresis systems. , 2002, Analytical chemistry.

[30]  Z. Demianová,et al.  Zone electrophoresis of proteins on a poly(methyl methacrylate) chip with conductivity detection. , 2003, Journal of chromatography. A.

[31]  L. Fu,et al.  Electrokinetic injection techniques in microfluidic chips. , 2002, Analytical chemistry.

[32]  D. J. Harrison,et al.  Planar chips technology for miniaturization and integration of separation techniques into monitoring systems. Capillary electrophoresis on a chip , 1992 .

[33]  Lung-Ming Fu,et al.  Variable‐volume‐injection methods using electrokinetic focusing on microfluidic chips , 2002 .

[34]  J. Bielčíková,et al.  Conductivity detection and quantitation of isotachophoretic analytes on a planar chip with on-line coupled separation channels. , 2001, Journal of chromatography. A.

[35]  D. J. Harrison,et al.  Design of an interface to allow microfluidic electrophoresis chips to drink from the fire hose of the external environment , 2001, Electrophoresis.

[36]  P. Fielden,et al.  A capacitively coupled conductivity detector for electroseparations , 2000 .

[37]  M. Morris,et al.  Isotachophoretic separations on a microchip. Normal Raman spectroscopy detection. , 1998, Analytical chemistry.

[38]  M. Masár,et al.  Determination of oxalate in beer by zone electrophoresis on a chip with conductivity detection , 2003 .

[39]  F. Regnier,et al.  Sampling BIAS at channel junctions in gated flow injection on chips. , 2002, Analytical chemistry.

[40]  A. Manz,et al.  Glass chips for high-speed capillary electrophoresis separations with submicrometer plate heights , 1993 .

[41]  J. Michael Ramsey,et al.  Electrokinetic Focusing in Microfabricated Channel Structures , 1997 .

[42]  Y. H. Lin,et al.  Flow-through sampling for electrophoresis-based microfluidic chips using hydrodynamic pumping. , 2001, Journal of chromatography. A.

[43]  J. Alarie,et al.  Effects of the electric field distribution on microchip valving performance , 2000, Electrophoresis.

[44]  N. Goddard,et al.  Determination of inorganic selenium species by miniaturised isotachophoresis on a planar polymer chip , 2003, Analytical and bioanalytical chemistry.

[45]  R. Bodor,et al.  Isotachophoresis and isotachophoresis-zone electrophoresis of food additives on a chip with column-coupling separation channels , 2001 .

[46]  Andreas Manz,et al.  Planar glass chips for capillary electrophoresis: repetitive sample injection, quantitation, and separation efficiency , 1993 .

[47]  D. J. Harrison,et al.  Effects of injector geometry and sample matrix on injection and sample loading in integrated capillary electrophoresis devices , 1999, Electrophoresis.

[48]  Lung-Ming Fu,et al.  Electrokinetic focusing injection methods on microfluidic devices. , 2003, Analytical chemistry.

[49]  M. Gijs,et al.  Pressure pulse injection: a powerful alternative to electrokinetic sample loading in electrophoresis microchips. , 2003, Analytical chemistry.

[50]  R. Bodor,et al.  Electrophoretic separations on chips with hydrodynamically closed separation systems , 2003, Electrophoresis.