On-line sample pre-concentration in microfluidic devices: a review.

On-line sample preconcentration is an essential tool in the development of microfluidic-based separation platforms. In order to become more competitive with traditional separation techniques, the community must continue to develop newer and more novel methods to improve detection limits, remove unwanted sample matrix components that disrupt separation performance, and enrich/purify analytes for other chip-based actions. Our goal in this review is to familiarize the reader with many of the options available for on-chip concentration enhancement with a focus on those manuscripts that, in our assessment, best describe the fundamental principles that govern those enhancements. Sections discussing both electrophoretic and nonelectrophoretic modes of preconcentration are included with a focus on device design and mechanisms of preconcentration. This review is not meant to be a comprehensive collection of every available example, but our hope is that by learning how on-line sample concentration techniques are being applied today, the reader will be inspired to apply these techniques to further enhance their own programs.

[1]  So-Hee Park,et al.  Electrophoretic total analysis of trace tetracycline antibiotics in a microchip with amperometry , 2009, Electrophoresis.

[2]  L. Zhang,et al.  Microchip isoelectric focusing with monolithic immobilized pH gradient materials for proteins separation , 2009, Electrophoresis.

[3]  A. Tiselius.  Electrophoresis of serum globulin. I. , 1937, The Biochemical journal.

[4]  S. Fanali,et al.  System peaks in capillary zone electrophoresis: II. Experimental study of vacancy peaks , 1997 .

[5]  A. Vinther,et al.  Temperature elevations of the sample zone in free solution capillary electrophoresis under stacking conditions , 1991 .

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

[7]  Yoon-Bo Shim,et al.  Total analysis of endocrine disruptors in a microchip with gold nanoparticles , 2010, Electrophoresis.

[8]  Jerome P Ferrance,et al.  Separation of sperm and epithelial cells in a microfabricated device: potential application to forensic analysis of sexual assault evidence. , 2005, Analytical chemistry.

[9]  C. Henry,et al.  High-sensitivity microchip electrophoresis determination of inorganic anions and oxalate in atmospheric aerosols with adjustable selectivity and conductivity detection. , 2009, Journal of chromatography. A.

[10]  M. Macka,et al.  System peaks in capillary zone electrophoresis. 3. Practical rules for predicting the existence of system peaks in capillary zone electrophoresis of anions using indirect spectrophotometric detection , 1997, Electrophoresis.

[11]  F. Kohlrausch,et al.  Ueber Concentrations-Verschiebungen durch Electrolyse im Inneren von Lösungen und Lösungsgemischen , 1897 .

[12]  Greg E Collins,et al.  Microchip micellar electrokinetic chromatography separation of alkaloids with UV‐absorbance spectral detection , 2008, Electrophoresis.

[13]  Petr Boček,et al.  Stacking phenomena in electromigration: From basic principles to practical procedures , 2003, Electrophoresis.

[14]  Kazunori Hoshino,et al.  Microchip-based immunomagnetic detection of circulating tumor cells. , 2011, Lab on a chip.

[15]  Zhongqi Xu,et al.  Investigation of the pH gradient formation and cathodic drift in microchip isoelectric focusing with imaged UV detection , 2010, Electrophoresis.

[16]  James P Landers,et al.  A valveless microfluidic device for integrated solid phase extraction and polymerase chain reaction for short tandem repeat (STR) analysis. , 2011, The Analyst.

[17]  James P Landers,et al.  On-chip pumping for pressure mobilization of the focused zones following microchip isoelectric focusing. , 2007, Lab on a chip.

[18]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[19]  Alex Terray,et al.  Preparative optical chromatography with external collection and analysis. , 2008, Optics express.

[20]  S. Digumarthy,et al.  Isolation of rare circulating tumour cells in cancer patients by microchip technology , 2007, Nature.

[21]  Takehiko Kitamori,et al.  Microchip-based liquid-liquid extraction for gas-chromatography analysis of amphetamine-type stimulants in urine. , 2006, Journal of chromatography. A.

[22]  K. A. Wolfe,et al.  Microchip-based purification of DNA from biological samples. , 2003, Analytical chemistry.

[23]  Jerome P Ferrance,et al.  Chitosan as a polymer for pH-induced DNA capture in a totally aqueous system. , 2006, Analytical chemistry.

[24]  C. Henry,et al.  Improving MCE with electrochemical detection using a bubble cell and sample stacking techniques , 2009, Electrophoresis.

[25]  N. Kaji,et al.  Enhanced electrophoretic resolution of monosulfate glycosaminoglycan disaccharide isomers on poly(methyl methacrylate) chips , 2007, Electrophoresis.

[26]  Alex Terray,et al.  Cascade optical chromatography for sample fractionation. , 2009, Biomicrofluidics.

[27]  S. S. Bahga,et al.  High‐sensitivity detection using isotachophoresis with variable cross‐section geometry , 2011, Electrophoresis.

[28]  G. Collins,et al.  Development of a microfabricated impinger for on-chip gas phase sampling , 2005 .

[29]  Jerome P Ferrance,et al.  Microchip-based macroporous silica sol-gel monolith for efficient isolation of DNA from clinical samples. , 2006, Analytical chemistry.

[30]  Juan G Santiago,et al.  Coupled isotachophoretic preconcentration and electrophoretic separation using bidirectional isotachophoresis. , 2011, Analytical chemistry.

[31]  N F de Rooij,et al.  Sample preconcentration by field amplification stacking for microchip‐based capillary electrophoresis , 2001, Electrophoresis.

[32]  H. Helmholtz,et al.  Studien über electrische Grenzschichten , 1879 .

[33]  Wouter Olthuis,et al.  Microchip analysis of lithium in blood using moving boundary electrophoresis and zone electrophoresis , 2005, Electrophoresis.

[34]  Jerome P Ferrance,et al.  Dual-domain microchip-based process for volume reduction solid phase extraction of nucleic acids from dilute, large volume biological samples. , 2010, Analytical chemistry.

[35]  So-Hee Park,et al.  Electrophoretic analysis of food dyes using a miniaturized microfluidic system , 2008, Electrophoresis.

[36]  Yujuan Hua,et al.  On-chip solid phase extraction and enzyme digestion using cationic PolyE-323 coatings and porous polymer monoliths coupled to electrospray mass spectrometry. , 2011, Journal of chromatography. A.

[37]  D. J. Harrison,et al.  Multifunctional protein processing chip with integrated digestion, solid‐phase extraction, separation and electrospray , 2010, Electrophoresis.

[38]  Katie M. Horsman,et al.  Method for determining intracapillary solution temperatures: Application to sample zone heating for enhanced fluorescent labeling of proteins , 2006, Electrophoresis.

[39]  J. Landers,et al.  Volume reduction solid phase extraction of DNA from dilute, large-volume biological samples. , 2010, Forensic science international. Genetics.

[40]  W. Heineman,et al.  On-line sample preconcentration using field-amplified stacking injection in microchip capillary electrophoresis. , 2006, Analytical chemistry.

[41]  Hyun Park,et al.  Direct analysis of trace phenolics with a microchip: in-channel sample preconcentration, separation, and electrochemical detection. , 2006, Analytical chemistry.

[42]  R. Chien,et al.  Sample stacking in laboratory-on-a-chip devices. , 2001, Journal of chromatography. A.

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

[44]  Michael G. Roper,et al.  A fully integrated microfluidic genetic analysis system with sample-in–answer-out capability , 2006, Proceedings of the National Academy of Sciences.

[45]  Ring-Ling Chien,et al.  Controlling data quality and reproducibility of a high-sensitivity immunoassay using isotachophoresis in a microchip. , 2008, Analytical chemistry.

[46]  P. Boček,et al.  System peaks in capillary zone electrophoresis: I. Simple model of vacancy electrophoresis , 1997 .

[47]  A. Tiselius,et al.  Electrophoresis of serum globulin: Electrophoretic analysis of normal and immune sera. , 1937, The Biochemical journal.

[48]  M. Hennion,et al.  Integrated microdevice for preconcentration and separation of a wide variety of compounds by electrochromatography , 2009, Electrophoresis.

[49]  P. Righetti,et al.  Current trends in capillary isoelectric focusing of proteins. , 1997, Journal of chromatography. B, Biomedical sciences and applications.

[50]  P. Boček,et al.  Predicting Peak Symmetry in Capillary Zone Electrophoresis. Background Electrolytes with Two Co-ions: Schizophrenic Zone Broadening and the Role of System Peaks , 1998 .

[51]  James P Landers,et al.  Dynamic solid phase DNA extraction and PCR amplification in polyester-toner based microchip. , 2011, Analytical chemistry.

[52]  K. Isselbacher,et al.  Isolation of circulating tumor cells using a microvortex-generating herringbone-chip , 2010, Proceedings of the National Academy of Sciences.

[53]  Zhao-Lun Fang,et al.  Microfluidic chip-based liquid-liquid extraction and preconcentration using a subnanoliter-droplet trapping technique. , 2005, Lab on a chip.

[54]  Greg E Collins,et al.  Electroosmotic flow-based pump for liquid chromatography on a planar microchip. , 2008, Analytical chemistry.

[55]  Chien-Fu Chen,et al.  Polymer microchips integrating solid-phase extraction and high-performance liquid chromatography using reversed-phase polymethacrylate monoliths. , 2009, Analytical chemistry.

[56]  Rajiv Bharadwaj,et al.  Thousandfold signal increase using field‐amplified sample stacking for on‐chip electrophoresis , 2003, Electrophoresis.

[57]  Greg E Collins,et al.  Microchip‐based CEC of nitroaromatic and nitramine explosives using silica‐based sol–gel stationary phases from methyl‐ and ethyl‐trimethoxysilane precursors , 2006, Electrophoresis.

[58]  Daniel J Marchiarullo,et al.  Towards an integrated microfluidic device for spaceflight clinical diagnostics Microchip-based solid-phase extraction of hydroxyl radical markers. , 2008, Journal of chromatography. A.

[59]  Muhammad J A Shiddiky,et al.  Trace analysis of DNA: preconcentration, separation, and electrochemical detection in microchip electrophoresis using Au nanoparticles. , 2007, Analytical chemistry.

[60]  Bohuslav Gas,et al.  Kohlrausch regulating function and other conservation laws in electrophoresis , 2007, Electrophoresis.

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

[62]  Jerome P Ferrance,et al.  Chitosan-coated silica as a solid phase for RNA purification in a microfluidic device. , 2009, Analytical chemistry.