101
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Strategies for the on-line preconcentration and separation of hypolipidaemic drugs using micellar electrokinetic chromatography. J Chromatogr A 2010; 1217:386-93. [DOI: 10.1016/j.chroma.2009.11.043] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 11/13/2009] [Accepted: 11/16/2009] [Indexed: 11/22/2022]
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102
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Timerbaev AR. Inorganic species analysis by CE â An overview for 2007â2008. Electrophoresis 2010; 31:192-204. [DOI: 10.1002/elps.200900397] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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103
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Tran NT, Ayed I, Pallandre A, Taverna M. Recent innovations in protein separation on microchips by electrophoretic methods: An update. Electrophoresis 2010; 31:147-73. [DOI: 10.1002/elps.200900465] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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104
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Zhang W, Chen JF, Fan LY, Cao CX, Ren JC, Li S, Shao J. A novel isotachophoresis of cobalt and copper complexes by metal ion substitution reaction in a continuous moving chelation boundary. Analyst 2010; 135:140-8. [DOI: 10.1039/b912799b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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105
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Xu Z, Koshimidzu E, Hirokawa T. Electrokinetic sample injection for high-sensitivity CZE (part 2): Improving the quantitative repeatability and application of electrokinetic supercharging-CZE to the detection of atmospheric electrolytes. Electrophoresis 2009; 30:3534-9. [DOI: 10.1002/elps.200900198] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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106
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Choi K, Jin YG, Chung DS. In-line coupling of two-phase single drop microextraction and large volume stacking using an electroosmotic flow pump in nonaqueous capillary electrophoresis. J Chromatogr A 2009; 1216:6466-70. [DOI: 10.1016/j.chroma.2009.07.047] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 07/21/2009] [Accepted: 07/27/2009] [Indexed: 11/29/2022]
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107
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Kuo CH, Wang JH, Lee GB. A microfabricated CE chip for DNA pre-concentration and separation utilizing a normally closed valve. Electrophoresis 2009; 30:3228-35. [DOI: 10.1002/elps.200900112] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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108
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Liang H, Chen Y, Tian LJ, Zhang L. Recursion approach for moving neutralization boundary formed on IPG strips Part I: With strong alkali rehydration buffer. Electrophoresis 2009; 30:3134-43. [DOI: 10.1002/elps.200900087] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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109
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Mandaji M, Rübensam G, Hoff RB, Hillebrand S, Carrilho E, Kist TL. Sample stacking in CZE using dynamic thermal junctions II: analytes with high dpKa/dT crossing a single thermal junction in a BGE with low dpH/dT. Electrophoresis 2009; 30:1510-5. [PMID: 19350542 DOI: 10.1002/elps.200800585] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In a previous work [M. Mandaji, et al., this issue] a sample stacking method was theoretically modeled and experimentally demonstrated for analytes with low dpK(a)/dT (analytes carrying carboxylic groups) and BGEs with high dpH/dT (high pH-temperature-coefficients). In that work, buffer pH was modulated with temperature, inducing electrophoretic mobility changes in the analytes. In the present work, the opposite conditions are studied and tested, i.e. analytes with high dpK(a)/dT and BGEs that exhibit low dpH/dT. It is well known that organic bases such as amines, imidazoles, and benzimidazoles exhibit high dpK(a)/dT. Temperature variations induce instantaneous changes on the basicity of these and other basic groups. Therefore, the electrophoretic velocity of some analytes changes abruptly when temperature variations are applied along the capillary. This is true only if BGE pH remains constant or if it changes in the opposite direction of pK(a) of the analyte. The presence of hot and cold sections along the capillary also affects local viscosity, conductivity, and electric field strength. The effect of these variables on electrophoretic velocity and band stacking efficacy was also taken into account in the theoretical model presented. Finally, this stacking method is demonstrated for lysine partially derivatized with naphthalene-2,3-dicarboxaldehyde. In this case, the amino group of the lateral chain was left underivatized and only the alpha amino group was derivatized. Therefore, the basicity of the lateral amino group, and consequently the electrophoretic mobility, was modulated with temperature while the pH of the buffer used remained unchanged.
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Affiliation(s)
- Marcos Mandaji
- PPGBCM, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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Abstract
Sample stacking techniques remain an important tool for enhancement of the selectivity and sensitivity of analyses in contemporary CZE. This contribution reviews new knowledge on this topic published since 2006. It is organized according to the operational principles used, which include concentration adjustment, application of a pH step, MEKC and sweeping, and transient ITP. Techniques combining several of these principles and comparative studies are also included.
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Affiliation(s)
- Zdena Malá
- Institute of Analytical Chemistry of the ASCR, Brno, Czech Republic
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111
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112
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Electrokinetic and hydrodynamic injection: making the right choice for capillary electrophoresis. Bioanalysis 2009; 1:889-94. [DOI: 10.4155/bio.09.73] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Dr Michael Breadmore is an Australian Research Council Queen Elizabeth II fellow with interests in the development of miniaturised analytical systems for the improved ana lysis of drugs and metabolites in biological fluids. He is based at the Australian Center for Research on Separation Science (ACROSS) at the University of Tasmania, Australia. He has spent the last 10 years developing novel electrophoresis methods for a range of applications with a particular interest in new ways to enhance the sensitivity. CE is a powerful liquid-phase separation technique that is an attractive alternative to HPLC because of its small sample requirements, high resolving power and excellent mass detection limits. While there are many similarities between the two techniques, there are also many differences, some obvious, some subtle. One of the often overlooked differences is the way sample is injected. In HPLC, injection is a very minor component of the method and the choice is predominantly restricted to the choice of solvent and the injection volume. But in CE, it is vastly more complex, and development of an appropriate injection strategy should be given consideration during any method development. While the choice between hydrodynamic or electrokinetic injection may not initially be given any thought, selection of the right approach for the right application can lead to significant improvements in performance, particularly with regard to achieving the lowest detection limits possible. The question is how to decide the best way to inject for each application?
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113
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Oakley JA, Shaw KJ, Docker PT, Dyer CE, Greenman J, Greenway GM, Haswell SJ. Development of a bi-functional silica monolith for electro-osmotic pumping and DNA clean-up/extraction using gel-supported reagents in a microfluidic device. LAB ON A CHIP 2009; 9:1596-1600. [PMID: 19458868 DOI: 10.1039/b820553a] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A silica monolith used to support both electro-osmotic pumping (EOP) and the extraction/elution of DNA coupled with gel-supported reagents is described. The benefits of the combined EOP extraction/elution system were illustrated by combining DNA extraction and gene amplification using the polymerase chain reaction (PCR) process. All the reagents necessary for both processes were supported within pre-loaded gels that allow the reagents to be stored at 4 degrees C for up to four weeks in the microfluidic device. When carrying out an analysis the crude sample only needed to be hydrodynamically introduced into the device which was connected to an external computer controlled power supply via platinum wire electrodes. DNA was extracted with 65% efficiency after loading lysed cells onto a silica monolith. Ethanol contained within an agarose gel matrix was then used to wash unwanted debris away from the sample by EOP (100 V cm(-1) for 5 min). The retained DNA was subsequently eluted from the monolith by water contained in a second agarose gel, again by EOP using an electric field of 100 V cm(-1) for 5 min, and transferred into the PCR reagent containing gel. The eluted DNA in solution was successfully amplified by PCR, confirming that the concept of a complete self-contained microfluidic device could be realised for DNA sample clean up and amplification, using a simple pumping and on-chip reagent storage methodology.
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Affiliation(s)
- Jennifer A Oakley
- Department of Chemistry, The University of Hull, Cottingham Road, Kingston upon Hull, HU6 7RX, UK
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114
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Liu Q, Yang Y, Huang Y, Pan C, Nie Z, Yao S. Separation of acidic and basic proteins by CE with CTAB additive and its applications in peptide and protein profiling. Electrophoresis 2009; 30:2151-8. [DOI: 10.1002/elps.200800785] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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115
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Thabano JR, Breadmore MC, Hutchinson JP, Johns C, Haddad PR. Silica nanoparticle-templated methacrylic acid monoliths for in-line solid-phase extraction–capillary electrophoresis of basic analytes. J Chromatogr A 2009; 1216:4933-40. [DOI: 10.1016/j.chroma.2009.04.012] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 03/30/2009] [Accepted: 04/03/2009] [Indexed: 10/20/2022]
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116
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Davis NI, Mamunooru M, Vyas CA, Shackman JG. Capillary and Microfluidic Gradient Elution Isotachophoresis Coupled to Capillary Zone Electrophoresis for Femtomolar Amino Acid Detection Limits. Anal Chem 2009; 81:5452-9. [DOI: 10.1021/ac9006182] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nejea I. Davis
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122
| | - Manasa Mamunooru
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122
| | - Chandni A. Vyas
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122
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117
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Vyas CA, Mamunooru M, Shackman JG. Amino Acid Measurements from a High Conductivity Matrix by Gradient Elution Isotachophoresis. Chromatographia 2009. [DOI: 10.1365/s10337-009-1122-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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118
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Mandaji M, Rübensam G, Hoff RB, Hillebrand S, Carrilho E, Kist TL. Sample stacking in CZE using dynamic thermal junctions I. Analytes with low dpKa/dTcrossing a single thermally induced pH junction in a BGE with high dpH/dT. Electrophoresis 2009; 30:1501-9. [DOI: 10.1002/elps.200800584] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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119
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Reijenga JC. pH programming in capillary electrophoresis by means of temperature programming. J Chromatogr A 2009; 1216:3642-5. [DOI: 10.1016/j.chroma.2009.01.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 12/12/2008] [Accepted: 01/12/2009] [Indexed: 11/28/2022]
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120
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Dawod M, Breadmore MC, Guijt RM, Haddad PR. Counter-flow electrokinetic supercharging for the determination of non-steroidal anti-inflammatory drugs in water samples. J Chromatogr A 2009; 1216:3380-6. [DOI: 10.1016/j.chroma.2009.02.014] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Revised: 02/02/2009] [Accepted: 02/04/2009] [Indexed: 12/01/2022]
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121
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Aturki Z, D’Orazio G, Fanali S, Rocco A, Bortolotti F, Gottardo R, Tagliaro F. Capillary electrochromatographic separation of illicit drugs employing a cyano stationary phase. J Chromatogr A 2009; 1216:3652-9. [DOI: 10.1016/j.chroma.2008.12.041] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Revised: 12/03/2008] [Accepted: 12/15/2008] [Indexed: 11/15/2022]
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122
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Quirino JP. Analyte focusing by micelle collapse in CZE: Nanopreparation of neutrals. Electrophoresis 2009; 30:875-82. [DOI: 10.1002/elps.200801735] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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123
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Meighan MM, Staton SJR, Hayes MA. Bioanalytical separations using electric field gradient techniques. Electrophoresis 2009; 30:852-65. [DOI: 10.1002/elps.200800614] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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124
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Cao J, Qi LW, Liu EH, Zhang WD, Li P. Separation and on-line preconcentration by stacking and sweeping of charged analytes in the plant by microemulsion electrokinetic chromatography with nonionic surfactants. J Pharm Biomed Anal 2009; 49:475-80. [DOI: 10.1016/j.jpba.2008.10.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Revised: 10/07/2008] [Accepted: 10/09/2008] [Indexed: 10/21/2022]
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125
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Proczek G, Augustin V, Descroix S, Hennion MC. Integrated microdevice for preconcentration and separation of a wide variety of compounds by electrochromatography. Electrophoresis 2009; 30:515-24. [DOI: 10.1002/elps.200800308] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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126
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Separation and determination of nimesulide related substances for quality control purposes by micellar electrokinetic chromatography. J Pharm Biomed Anal 2009; 49:201-6. [DOI: 10.1016/j.jpba.2008.10.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2008] [Revised: 10/15/2008] [Accepted: 10/17/2008] [Indexed: 11/22/2022]
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127
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Xu L, Dong XY, Sun Y. Novel negatively charged tentacle-type polymer coating for on-line preconcentration of proteins in CE. Electrophoresis 2009; 30:689-95. [DOI: 10.1002/elps.200800558] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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128
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Xu Z, Esumi T, Ikuta N, Hirokawa T. High-sensitive analysis of DNA fragments by capillary gel electrophoresis using transient isotachophoresis preconcentration and fluorescence detection. J Chromatogr A 2009; 1216:3602-5. [PMID: 19211105 DOI: 10.1016/j.chroma.2009.01.066] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 01/21/2009] [Accepted: 01/23/2009] [Indexed: 01/15/2023]
Abstract
In this report aimed on further development of a high-sensitivity capillary gel electrophoresis (CGE) method for analysis of DNA fragments, we firstly explored online transient isotachophoresis (tITP) preconcentration combined with fluorescence detection (FD). The fluorescence signal (excitation: 488 nm; emission: 590 nm) was generated using the intercalating dye of ethidium bromide (EB). It was found when the leading electrolyte (LE) was injected behind the sample zone, such a special tITP mode has significant advantages to solve the bubble formation issue and to improve the analytical performance stability. Two standard DNA samples, a 50 bp DNA step ladder and the phiX174/HaeIII digest, were used to evaluate the qualitative and quantitative abilities of the tITP-FD approach. A highly diluted sample (10,000-fold in the water, e.g. the phiX174/HaeIII digest diluted from 500 microg/ml to the 50 ng/ml level) was enriched and detected; the LOD was down to 0.09 ng/ml for the 72 bp fragment, apparently improved more than 1000-fold in comparison with UV detection. Although the RSD of peak areas (n=3) was around 15.5% for the sample was electrokinetically injected, good linearity of peak area response showed that the proposed method is suitable for quantitative analysis.
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Affiliation(s)
- Zhongqi Xu
- Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-hiroshima, Japan
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129
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High-sensitivity capillary and microchip electrophoresis using electrokinetic supercharging preconcentration. J Chromatogr A 2009; 1216:660-70. [DOI: 10.1016/j.chroma.2008.10.077] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 10/02/2008] [Accepted: 10/07/2008] [Indexed: 11/24/2022]
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130
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Breadmore MC, Thabano JRE, Dawod M, Kazarian AA, Quirino JP, Guijt RM. Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2006-2008). Electrophoresis 2009; 30:230-48. [DOI: 10.1002/elps.200800435] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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131
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Yeung SHI, Liu P, Del Bueno N, Greenspoon SA, Mathies RA. Integrated Sample Cleanup−Capillary Electrophoresis Microchip for High-Performance Short Tandem Repeat Genetic Analysis. Anal Chem 2008; 81:210-7. [DOI: 10.1021/ac8018685] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stephanie H. I. Yeung
- UCSF/UCB Joint Graduate Group in Bioengineering, University of California, Berkeley, California 94720, Virginia Department of Forensic Science, Richmond, Virginia 23219, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Peng Liu
- UCSF/UCB Joint Graduate Group in Bioengineering, University of California, Berkeley, California 94720, Virginia Department of Forensic Science, Richmond, Virginia 23219, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Nadia Del Bueno
- UCSF/UCB Joint Graduate Group in Bioengineering, University of California, Berkeley, California 94720, Virginia Department of Forensic Science, Richmond, Virginia 23219, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Susan A. Greenspoon
- UCSF/UCB Joint Graduate Group in Bioengineering, University of California, Berkeley, California 94720, Virginia Department of Forensic Science, Richmond, Virginia 23219, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Richard A. Mathies
- UCSF/UCB Joint Graduate Group in Bioengineering, University of California, Berkeley, California 94720, Virginia Department of Forensic Science, Richmond, Virginia 23219, and Department of Chemistry, University of California, Berkeley, California 94720
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132
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Neutral analyte focusing by micelle collapse in micellar electrokinetic chromatography. J Chromatogr A 2008; 1214:171-7. [DOI: 10.1016/j.chroma.2008.10.074] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2008] [Revised: 10/15/2008] [Accepted: 10/17/2008] [Indexed: 11/20/2022]
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133
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Label-free fluorescence detection in capillary and microchip electrophoresis. Anal Bioanal Chem 2008; 393:515-25. [PMID: 18982318 DOI: 10.1007/s00216-008-2452-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 09/18/2008] [Accepted: 10/01/2008] [Indexed: 12/14/2022]
Abstract
Herein, we summarize the current status of native fluorescence detection in microchannel electrophoresis, with a strong focus on chip-based systems. Fluorescence detection is a powerful technique with unsurpassed sensitivity down to the single-molecule level. Accordingly fluorescence detection is attractive in combination with miniaturised separation techniques. A drawback is, however, the need to derivatize most analytes prior to analysis. This can often be circumvented by utilising excitation light in the UV spectral range in order to excite intrinsic fluorescence. As sensitive absorbance detection is challenging in chip-based systems, deep-UV fluorescence detection is currently one of the most general optical detection techniques in microchip electrophoresis, which is especially attractive for the detection of unlabelled proteins. This review gives an overview of research on native fluorescence detection in capillary (CE) and microchip electrophoresis (MCE) between 1998 and 2008. It discusses material aspects of native fluorescence detection and the instrumentation used, with particular focus on the detector design. Newer developments, featured techniques, and their prospects in the future are also included. In the last section, applications in bioanalysis, drug determination, and environmental analysis are reviewed with regard to limits of detection.
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134
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Sueyoshi K, Kitagawa F, Otsuka K. Recent progress of online sample preconcentration techniques in microchip electrophoresis. J Sep Sci 2008; 31:2650-66. [PMID: 18693308 DOI: 10.1002/jssc.200800272] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Microchip electrophoresis (MCE) has been advanced remarkably by the applications of several separation modes and the integration with several chemical operations on a single planer substrate. MCE shows superior analytical performance, e.g., high-speed analysis, high resolution, low consumption of reagents, and so on, whereas low-concentration sensitivity is still one of the major problems. To overcome this drawback, various online sample preconcentration techniques have been developed in MCE over the past 15 years, which have successfully enhanced the detection sensitivity in MCE. This review highlights recent developments in online sample preconcentration in MCE categorized on the basis of "dynamic" and "static" methods. The dynamic techniques including field amplified stacking, ITP, sweeping, and focusing have been easily applied to MCE, which provide effective enrichments of various analytes. The static techniques such as SPE and filtration have also been combined with MCE. In the static techniques, extremely high preconcentration efficiency can be obtained, compared to the dynamic methods. This review provides comprehensive tables listing the applications and sensitivity enhancement factors of these preconcentration techniques employed in MCE.
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Affiliation(s)
- Kenji Sueyoshi
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan.
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135
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Electrokinetic sample injection for high‐sensitivity capillary zone electrophoresis (part 1): Effects of electrode configuration and setting. Electrophoresis 2008; 29:3786-93. [DOI: 10.1002/elps.200800172] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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136
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137
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Yamamoto S, Hirakawa S, Suzuki S. In situ fabrication of ionic polyacrylamide-based preconcentrator on a simple poly(methyl methacrylate) microfluidic chip for capillary electrophoresis of anionic compounds. Anal Chem 2008; 80:8224-30. [PMID: 18841941 DOI: 10.1021/ac801245n] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A simple and efficient method was developed for fabrication of an anionic sample preconcentrator on a channel of a commercial poly(methyl methacrylate) (PMMA)-made microchip using no photolithography or etching technique. The originality of our preconcentrator is based on simple photochemical copolymerization of monomers using the following procedure: All channels of the PMMA-made microchip were filled with gel solution comprising acrylamide, N,N'-methylene-bisacrylamide, and 2-acrylamide-2-methylpropanesulfonic acid with riboflavin as a photocatalytic initiator. In situ polymerization near the cross of the sample outlet channel was performed by irradiation with an argon ion laser beam, which is also used as the light source for fluorometric detection. The electrokinetic property and electric repulsion between sample components and anionic groups on the polyacrylamide gel layer produce, trap, and concentrate anions within a few minutes at the interface of the cathodic side of the gel layer. This method displays concentration factors as high as 10 (5). The availability of ionic preconcentrator was demonstrated by applying sensitive analysis of oligosaccharides labeled with 8-aminopyrene-1,3,6-trisulfonate and some glycoproteins labeled with fluorescein isothiocyanate under various buffer systems.
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Affiliation(s)
- Sachio Yamamoto
- School of Pharmacy, Kinki University, 3-4-1, Kowakae, Higashi-osaka, Japan
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138
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Determination of linezolid and its achiral impurities using sweeping preconcentration by micellar capillary electrophoresis. J Pharm Biomed Anal 2008; 48:321-30. [DOI: 10.1016/j.jpba.2008.01.025] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2007] [Revised: 01/08/2008] [Accepted: 01/14/2008] [Indexed: 11/21/2022]
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139
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Hernández E, Benavente F, Sanz-Nebot V, Barbosa J. Evaluation of on-line solid phase extraction-capillary electrophoresis-electrospray-mass spectrometry for the analysis of neuropeptides in human plasma. Electrophoresis 2008; 29:3366-76. [DOI: 10.1002/elps.200700872] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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140
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Mamunooru M, Jenkins RJ, Davis NI, Shackman JG. Gradient elution isotachophoresis with direct ultraviolet absorption detection for sensitive amino acid analysis. J Chromatogr A 2008; 1202:203-11. [DOI: 10.1016/j.chroma.2008.07.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Revised: 06/09/2008] [Accepted: 07/02/2008] [Indexed: 11/27/2022]
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141
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Guzman NA, Blanc T, Phillips TM. Immunoaffinity capillary electrophoresis as a powerful strategy for the quantification of low-abundance biomarkers, drugs, and metabolites in biological matrices. Electrophoresis 2008; 29:3259-78. [PMID: 18646282 PMCID: PMC2659498 DOI: 10.1002/elps.200800058] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In the last few years, there has been a greater appreciation by the scientific community of how separation science has contributed to the advancement of biomedical research. Despite past contributions in facilitating several biomedical breakthroughs, separation sciences still urgently need the development of improved methods for the separation and detection of biological and chemical substances. In particular, the challenging task of quantifying small molecules and biomolecules, found in low abundance in complex matrices (e.g., serum), is a particular area in need of new high-efficiency techniques. The tandem or on-line coupling of highly selective antibody capture agents with the high-resolving power of CE is being recognized as a powerful analytical tool for the enrichment and quantification of ultra-low abundance analytes in complex matrices. This development will have a significant impact on the identification and characterization of many putative biomarkers and on biomedical research in general. Immunoaffinity CE (IACE) technology is rapidly emerging as the most promising method for the analysis of low-abundance biomarkers; its power comes from a three-step procedure: (i) bioselective adsorption and (ii) subsequent recovery of compounds from an immobilized affinity ligand followed by (iii) separation of the enriched compounds. This technology is highly suited to automation and can be engineered to as a multiplex instrument capable of routinely performing hundreds of assays per day. Furthermore, a significant enhancement in sensitivity can be achieved for the purified and enriched affinity targeted analytes. Thus, a compound that exists in a complex biological matrix at a concentration far below its LOD is easily brought to well within its range of quantification. The present review summarizes several applications of IACE, as well as a chronological description of the improvements made in the fabrication of the analyte concentrator-microreactor device leading to the development of a multidimensional biomarker analyzer.
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Affiliation(s)
- Norberto A Guzman
- Biomarker Laboratory, Princeton Biochemicals, Inc., Princeton, NJ 08543, USA.
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142
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Method for determination of total cysteamine in human plasma by high performance capillary electrophoresis with acetonitrile stacking. Electrophoresis 2008; 29:3636-40. [DOI: 10.1002/elps.200800034] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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143
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Lin YT, Kou HS, Wu HL. A simple micellar electrokinetic capillary chromatographic method for the quantitative analysis of organic expectorants. Electrophoresis 2008; 29:3524-30. [DOI: 10.1002/elps.200800129] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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144
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Hou C, Herr AE. Clinically relevant advances in on-chip affinity-based electrophoresis and electrochromatography. Electrophoresis 2008; 29:3306-19. [DOI: 10.1002/elps.200800244] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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145
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Almeda S, Arce L, Valcárcel M. Combined use of supported liquid membrane and solid-phase extraction to enhance selectivity and sensitivity in capillary electrophoresis for the determination of ochratoxin A in wine. Electrophoresis 2008; 29:1573-81. [PMID: 18318446 DOI: 10.1002/elps.200700372] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This paper proposes a novel strategy to enhance selectivity and sensitivity in CE, using supported liquid membrane (SLM) and off-line SPE simultaneously. The determination of ochratoxin A (OA) in wine has been used to demonstrate the potential of this methodology. In the SLM step, the donor phase (either a 20 mL volume of a standard solution at pH 1 or a wine sample at pH 8) was placed in a vial, where a micromembrane extraction unit accommodating the acceptor phase (1 mL water, pH 11) in its lumen was immersed. The SLM was constructed by impregnating a porous Fluoropore Teflon (PTFE) membrane with a water-immiscible organic solvent (octanol). In the off-line SPE step, the nonpolar sorbent (C-18, 4 mg) selectively retained the target ochratoxin, enabling small volumes of acceptor phase (1 mL) to be introduced. The captured analytes were eluted in a small volume of methanol (0.1 mL). This procedure resulted in sample cleanup and concentration enhancement. The method was evaluated for accuracy and precision, and its RSD found to be 5%. The LODs for OA in the standard solutions and wine samples were 0.5 and 30 microg/L, respectively. The results obtained demonstrate that SLM combined with off-line is a good alternative to the use of immunoaffinity columns prior to CE analysis.
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Affiliation(s)
- Sara Almeda
- Department of Analytical Chemistry, University of Cordoba, Campus de Rabanales, Cordoba, Spain
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146
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Kazarian AA, Hilder EF, Breadmore MC. Utilisation of pH stacking in conjunction with a highly absorbing chromophore, 5-aminofluorescein, to improve the sensitivity of capillary electrophoresis for carbohydrate analysis. J Chromatogr A 2008; 1200:84-91. [PMID: 18468613 DOI: 10.1016/j.chroma.2008.04.022] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2008] [Revised: 04/09/2008] [Accepted: 04/11/2008] [Indexed: 11/30/2022]
Abstract
This study explores the use of pH stacking in conjunction with 5-aminofluorescein as a derivatization agent for the sensitive analysis of simple sugars such as glucose, lactose and maltotriose by capillary electrophoresis (CE). The derivatization agent was selected on the basis of its extremely high molar absorptivity, its compatibility with a 488nm light-emitting diode (LED) and the fact that it has two ionizable groups making it compatible with on-line stacking using a dynamic pH junction. The influence of both acetic and formic acids at concentrations of 0.19, 0.019 and 0.0019molL(-1) were investigated with regard to both derivatization efficiency and the ability to stack using a dynamic pH junction. Superior sensitivity and resolution was obtained in formic acid over acetic acid. Substantially lower peaks were obtained with 0.19molL(-1) formic acid when compared to 0.019 and 0.0019molL(-1) concentrations, which was confirmed by computer simulation studies to be due to the inadequate movement of the pH boundary for stacking. Further simulation studies combined with experimental data showed the separation with the best resolution and greatest sensitivity when the carbohydrates were derivatized with the 0.095molL(-1) formic acid. Utilisation of stacking via dynamic pH junction mode in conjunction with LED detection enabled efficiencies of 150,000 plates and detection limits in the order of 8.5x10(-8)molL(-1) for simple sugars such as glucose, lactose and maltotriose hydrate. The current system also demonstrates a 515 times improvement in sensitivity when compared to using a normal deuterium lamp, and 16 times improvement over other systems using LEDs.
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Affiliation(s)
- Artaches A Kazarian
- Australian Centre for Research on Separation Science, School of Chemistry, University of Tasmania, GPO Box 252-75, Hobart, Tasmania 7001, Australia
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147
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Breadmore MC, Quirino JP. 100 000-Fold Concentration of Anions in Capillary Zone Electrophoresis Using Electroosmotic Flow Controlled Counterflow Isotachophoretic Stacking under Field Amplified Conditions. Anal Chem 2008; 80:6373-81. [DOI: 10.1021/ac8007835] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michael C. Breadmore
- Australian Centre for Research on Separation Science, School of Chemistry, University of Tasmania, G.P.O. Box 252-75, Hobart, Tasmania 7001, Australia
| | - Joselito P. Quirino
- Australian Centre for Research on Separation Science, School of Chemistry, University of Tasmania, G.P.O. Box 252-75, Hobart, Tasmania 7001, Australia
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148
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Blanco E, Casais MDC, Mejuto MDC, Cela R. Simultaneous determination of p-hydroxybenzoic acid and parabens by capillary electrophoresis with improved sensitivity in nonaqueous media. Electrophoresis 2008; 29:3229-38. [DOI: 10.1002/elps.200700916] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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149
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Morales-Cid G, Simonet BM, Cárdenas S, Valcárcel M. Electrical field-assisted solid-phase extraction coupled on-line to capillary electrophoresis-mass spectrometry. Electrophoresis 2008; 29:2033-40. [DOI: 10.1002/elps.200700565] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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150
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Puig P, Borrull F, Calull M, Aguilar C. Sorbent preconcentration procedures coupled to capillary electrophoresis for environmental and biological applications. Anal Chim Acta 2008; 616:1-18. [DOI: 10.1016/j.aca.2008.03.062] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Revised: 03/14/2008] [Accepted: 03/31/2008] [Indexed: 11/27/2022]
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