The more and less common approaches to enhancing sensitivity in capillary electrophoresis

Current Analytical Chemistry

Volumn 6, Issue 2, 2010, Pages 126-143

  Almeda, S ^a   Arce, L ^a   Valcarcel M ^a  

^a UNIVERSITY OF CÓRDOBA   (Spain)

Author keywords

Capillary electrophoresis; Preconcentration; Sensitivity

Indexed keywords

EFFLUENT TREATMENT; PHASE SEPARATION; SUPERCRITICAL FLUID EXTRACTION; SUPERCRITICAL FLUIDS;

ANALYSIS TIME; ANALYTICAL PROCESS; ENVIRONMENTAL FRIENDLY APPROACH; POTENTIAL ERRORS; PRE-CONCENTRATION; SAMPLE MATRIX; SAMPLE PRECONCENTRATION; SAMPLE SIZES; SENSITIVITY; TRACE ANALYTES;

CAPILLARY ELECTROPHORESIS;

EID: 78349294115     PISSN: 15734110     EISSN: None     Source Type: Journal    
DOI: 10.2174/157341110790945508     Document Type: Article

References (168)

1. Khaleddi, M.G. High-Performance Capillary Electrophoresis:Theory, Techniques, and Applications. John Willey&Sons Inc.:New York, 1998.
2. Landers, J.P. Handbook of Capillary and Microchip Electrophoresisand Associated Microtechnics. CRC Press: Taylor & FrancisGroup: Boca Raton, 2008.
3. Hernández-Borges, J.; Borges-Miquel, T.M.; Rodriguez-Delgado, M.A.; Cifuentes, A. Sample treatments prior to capillary electrophoresis-mass spectrometry. J. Chromatogr. A, 2007, 1153, 214-226.
4. Analysis and detection by capillary electrophoresis, XLV, Elsevier:Amsterdam, 2005.
5. Simonet, B.M.; Ríos, A.; Valcárcel, M. Enhancing sensitivity incapillary electrophoresis. Trends Anal. Chem., 2003, 22, 605-614.
6. Breadmore, M.C. Recent advances in enhancing the sensitivity ofelectrophoresis and electrochromatography in capillaries and microchips. Electrophoresis, 2007, 28, 254-281.
7. Majors, R.E. Sample preparation for HPLC and GC using solidphase extraction. LC-GC, 1986, 4, 972.
8. Meyer, H.E.; Hoffmannposorske, E.; Korte, H.; Donelladeana, A.; Brunati, A.M.; Pinna, L.A.; Coull, J.; Perich, J.; Valerio, R.M.; Johns, R.B. Sequence-analysis of phosphotyrosine-containing peptides - determination of PTH-phosphotyrosine by capillary electrophoresis. Chromatographia, 1990, 30, 691-695.
9. Scheppers, S.A.; Pawliszyn, J. Solid-Phase Microextraction: APractical Guide, Marcel Deker: New York, 1999.
10. Visser, N.F.C.; van Harmelen, M.; Lingeman, H.; Irth, H. On-lineSPE-CE for the determination of insulin derivatives in biologicalfluids. J. Pharm. Biomed. Anal., 2003, 33, 451-462.
11. Saavedra, L.; Barbas, C. Chromatography-based on- and in-linepre-concentration methods in capillary electrophoresis. J. Biochem. Biophys. Methods, 2007, 70, 289-297.
12. Ramautar, R.; Ratnayake, C.K.; Somsen, G.W.; de Jong, G.J. Capillaryelectrophoresis-mass spectrometry using an in-line sol-gelconcentrator for the determination of methionine enkephalin incerebrospinal fluid. Talanta, 2009, 78, 638-642.
13. Puig, P.; Borrull, F.; Calull, M.; Aguilar, C. Recent advances incoupling solid-phase extraction and capillary electrophoresis (SPECE). Trends Anal. Chem., 2007, 26, 664-678.
14. Puig, P.; Borrull, F.; Calull, M.; Aguilar, C. Sorbent preconcentrationprocedures coupled to capillary electrophoresis for environmentaland biological applications. Anal. Chim. Acta, 2008, 616, 1-18.
15. van de Merbel, N.C. Membrane-based sample preparation coupledon-line to chromatography or electrophoresis. J. Chromatogr. A, 1999, 856, 55-82.
16. Noble, R.D.; Way, J.D. Liquid Membrane: Theory and Applications, American Chemical Society: Washington (USA), 1987.
17. Jonsson, J.A.; Mathiasson, L. Membrane extraction techniques forsample preparation. Adv. Chromatogr., 2001, 41, 53-91.
18. Audunsson, G. Aqueous extraction by means of a liquid membranefor sample cleanup and preconcentration of amines in a flow system. Anal. Chem., 1986, 58, 2714-2723.
19. Nozal, L.; Arce, L.; Simonet, B.M.; Ríos, A.; Valcárcel, M. Newsupported liquid membrane-capillary electrophoresis in-line arrangementfor direct selective analysis of complex samples. Electrophoresis, 2006, 27, 3075-3085.
20. Pedersen-Bjergaard, S.; Rasmussen, K.E. Liquid-phase microextractionwith porous hollow fibers, a miniaturized and highly flexibleformat for liquid-liquid extraction. J. Chromatogr. A, 2008, 1184, 132-142.
21. Danesi, P.R. Separation of metal species by supported liquid membranes. Sep. Sci. Technol., 1984, 19, 857-894.
22. Wijers, M.C.; Jin, M.; Wessling, M.; Strathmann, H. Supportedliquid membranes modification with sulphonated poly(ether etherketone) - Permeability, selectivity and stability. J. Membr. Sci., 1998, 147, 117-130.
23. Naylor, S.; Tomlinson, A.J. Membrane preconcentration-capillaryelectrophoresis tandem mass spectrometry (mPC-CE-MS/MS) inthe sequence analysis of biologically derived peptides. Talanta, 1998, 45, 603-612.
24. Palmarsdottir, S.; Mathiasson, L.; Jonsson, J.A.; Edholm, L.E. Determination of a basic drug, bambuterol, in human plasma bycapillary electrophoresis using double stacking for large volume injectionand supported liquid membranes for sample pretreatment. J. Chromatogr. B, 1997, 688, 127-134.
25. Pedersen-Bjergaard, S.; Rasmussen, K.E.; Halvorsen, T.G. Liquidliquidextraction procedures for sample enrichment in capillaryzone electrophoresis. J. Chromatogr. A, 2000, 902, 91-105.
26. Rasmussen, K.E.; Pedersen-Biergaard, S. Developments in hollowfibre-based, liquid-phase microextraction. Trends Anal. Chem., 2004, 23, 1-10.
27. Valcárcel, M.; Arce, L.; Ríos, A. Coupling continuous separationtechniques to capillary electrophoresis. J. Chromatogr. A, 2001, 924, 3-30.
28. Almeda, S.; Arce, L.; Valcárcel, M. Combined use of supportedliquid membrane and solid-phase extraction to enhance selectivityand sensitivity in capillary electrophoresis for the determination ofochratoxin A in wine. Electrophoresis, 2008, 29, 1573-1581.
29. Almeda, S.; Arce, L.; Nozal, L.; Valcárcel, M. Direct determinationof chlorophenols present in liquid samples by using a supportedliquid membrane coupled in-line with capillary electrophoresisequipment. Anal. Chim. Acta, 2007, 587, 97-103.
30. Danger, G.; Pascal, R.; Cottet, H. On-line sample stacking of peptidesin capillary electrophoresis for the study of prebiotic reactionsbetween α,α-dialkylated amino acids and amino acid Ncarboxyanhydrides. J. Chromatogr. A, 2009, 1213, 5748-5754.
31. Gebauer, P.; Bocek, P. Electrophoretic sample stacking. Electrophoresis, 2009, 30, S27-S33.
32. Karasova, L.A.; Bessonova, E.A. Preconcentration techniques incapillary electrophoresis. J. Anal. Chem., 2009, 64, 326-337.
33. Mala, Z.; Slampova, A.; Gebauer, P.; Bocek, P. Contemporarysample stacking in CE. Electrophoresis, 2009, 30, 215-229.
34. Simpson, S.L.; Quirino, J.P.; Terabe, S. On-line sample preconcentrationin capillary electrophoresis fundamentals and applications. J. Chromatogr. A, 2008, 1184, 504-541.
35. Xia, S.F.; Zhang, L.; Qiu, B.; Lu, M.H.; Chi, Y.W.; Chen, G.N. On-line preconcentration and quantitative analysis of peptide hormoneof brain and intestine using on-column transient isotachophoresiscoupled with capillary electrophoresis/electrospray ionizationmass spectrometry. Rapid Commun. Mass Spectrom., 2008, 22, 3719-3726.
36. Krivankova, L.; Gebauer, P.; Bocek, P. Some practical aspects ofutilizing the on-line combination of isotachophoresis and capillaryzone electrophoresis. J. Chromatogr. A, 1995, 716, 35-48.
37. Krivankova, L.; Bocek, P. Synergism of capillary isotachophoresisand capillary zone electrophoresis. J. Chromatogr. B, 1997, 689, 13-34.
38. Kaniansky, D.; Marak, J. On-line coupling of capillary isotachophoresiswith capillary zone electrophoresis. J. Chromatogr., 1990, 498, 204.
39. Kaniansky, D.; Marak, J.; Lastinec, J.; Reijenga, J.C.; Onuska, F.I. Capillary zone electrophoresis with on-line isotachophoretic samplepretreatment: Sample clean-up aspects. J. Microcol. Sep., 1999, 11, 141-153.
40. Monton, M.R.N.; Terabe, S. Sample enrichment techniques incapillary electrophoresis: Focus on peptides and proteins. J. Chromatogr.B, 2006, 841, 88-95.
41. Britz-McKibbin, P.; Terabe, S. On-line preconcentration strategiesfor trace analysis of metabolites by capillary electrophoresis. J. Chromatogr. A, 2003, 1000, 917-934.
42. Lin, C.H.; Kaneta, T. On-line sample concentration techniques incapillary electrophoresis: Velocity gradient techniques and sampleconcentration techniques for biomolecules. Electrophoresis, 2004, 25, 4058-4073.
43. Silva, M. Micellar electrokinetic chromatography: Methodologicaland instrumental advances focused on practical aspects. Electrophoresis, 2009, 30, 50-64.
44. Mikkers, F.E.P.; Everaerts, F.M.; Verheggen, T.P.E.M. High performance zone electrophoresis. J. Chromatogr., 1979, 169, 11-20.
45. Burgi, D.S. Large-volume stacking of anions in capillary electrophoresisusing an electroosmotic flow modifier as a pump. Anal. Chem., 1993, 65, 3726-3729.
46. Macia, A.; Borrull, F.; Aguilar, C.; Calull, M. Application of capillaryelectrophoresis with different sample stacking strategies for thedetermination of a group of nonsteroidal anti-inflammatory drugsin the low μg*L-1 concentration range. Electrophoresis, 2004, 25, 428-436.
47. Albert, M.; Debusschere, L.; Demesmay, C.; Rocca, J.L. Largevolumestacking for quantitative analysis of anions in capillaryelectrophoresis. I. Large-volume stacking with polarity switching. J. Chromatogr. A, 1997, 757, 291-296.
48. Harland, G.B.; McGrath, G.; McClean, S.; Smyth, W.F. Use oflarge volume sample stacking for improving limits of detection inthe capillary electrophoretic determination of selected cations. Anal. Commun., 1997, 34, 9-11.
49. McGrath, G.; Smyth, W.F. Large-volume sample stacking of selecteddrugs of forensic significance by capillary electrophoresis. J. Chromatogr. B, 1996, 681, 125-131.
50. Smyth, W.F.; Harland, G.B.; McClean, S.; McGrath, G.; Oxspring, D. Effect of on-capillary large volume sample stacking on limits ofdetection in the capillary zone electrophoretic determination of selecteddrugs, dyes and metal chelates. J. Chromatogr. A, 1997, 772, 161-169.
51. McClean, S.; O'Kane, E.; Coulter, D.J.M.; McLean, S.; Smyth, W.F. Capillary electrophoretic determination of trace metals in hairsamples and its comparison with high performance liquid chromatographyand atomic absorption spectrometry techniques. Electrophoresis, 1998, 19, 11-18.
52. Hissner, F.; Daus, B.; Mattusch, J.; Heinig, K. Determination offlotation reagents used in tin-mining by capillary electrophoresis. J. Chromatogr. A, 1999, 853, 497-502.
53. Martinez, D.; Borrull, F.; Calull, M. Sample stacking using fieldamplifiedsample injection in capillary zone electrophoresis in theanalysis of phenolic compounds. J. Chromatogr. A, 1997, 788, 185-193.
54. Quirino, J.P.; Terabe, S. Sample stacking of fast-moving anions incapillary zone electrophoresis with pH-suppressed electroosmoticflow. J. Chromatogr. A, 1999, 850, 339-344.
55. Zhu, L.Y.; Lee, H.K. Field amplified sample injection combinedwith water removal by electroosmotic flow pump in acidic bufferfor analysis of phenoxy acid herbicides by capillary electrophoresis. Anal. Chem., 2001, 73, 3065-3072.
56. Hirokawa, T.; Ohmori, A.; Kiso, Y. Analysis of a dilute sample bycapillary zone electrophoresis with isotachophoretic preconcentration. J. Chromatogr., 1993, 634, 101-106.
57. Jung, B.; Bharadwaj, R.; Santiago, J.G. Thousandfold signal increaseusing field-amplified sample stacking for on-chip electrophoresis. Electrophoresis, 2003, 24, 3476-3483.
58. Jung, B.; Bharadwaj, R.; Santiago, J.G. On-chip millionfold samplestacking using transient isotachophoresis. Anal. Chem., 2006, 78, 2319-2327.
59. Wang, C.; Han, D.; Wang, Z.; Zang, X.; Wu, Q. Analysis ofStrychnos alkaloids in traditional Chinese medicines with improvedsensitivity by sweeping micellar electrokinetic chromatography. Anal. Chim. Acta., 2006, 572, 190-196.
60. Shihabi, Z.K. Transient pseudo-isotachophoresis for sample concentrationin capillary electrophoresis. Electrophoresis, 2002, 23, 1612-1617.
61. Cañada-Cañada, F.; Kasselouri, A.; Prognon, P.; Maillard, P.; Grierson, D.S.; Descroix, S.; Taverna, M. Enhanced detection of sevenglucoconjugated and hydroxylated porphyrins and chlorins bynonaqueous capillary electrophoresis combined with stacking. J. Chromatogr. A, 2003, 1068, 123-130.
62. Kong, Y.; Zheng, N.; Zhang, Z.; Gao, R. Optimization stacking bytransient pseudo-isotachophoresis for capillary electrophoresis: Exampleanalysis of plasma glutathione. J. Chromatogr. B, 2003, 795, 9-15.
63. Kubalczyk, P.; Bald, E. Transient pseudo-isotachophoretic stackingin analysis of plasma for homocysteine by capillary zoneelectrophoresis. Anal. Bioanal. Chem., 2006, 384, 1181-1185.
64. Foret, F.; Szoko, E.; Karger, B.L. On-column transient and coupledcolumn isotachophoretic preconcentration of protein samples incapillary zone electrophoresis. J. Chromatogr., 1992, 608, 3-12.
65. Mazereeuw, M.; Tjaden, U.R.; Reinhoud, N.J. Single capillaryisotachophoresis-zone electrophoresis - current practice and prospects, a review. J. Chromatogr. Sci., 1995, 33, 686-697.
66. Michalke, B.; Schramel, P. Capillary electrophoresis interfaced toinductively coupled plasma mass spectrometry for element selectivedetection in arsenic speciation. Electrophoresis, 1998, 19, 2220-2225.
67. Dankova, M.; Kaniansky, D.; Fanali, S.; Ivanyi, F. Capillary zoneelectrophoresis separations of enantiomers present in complex ionicmatrices with on-line isotachophoretic sample pretreatment. J. Chromatogr. A, 1999, 838, 31-43.
68. Larsson, M.; Nagard, S. On-column ITP focusing in CZE for thequantitation of low-molecular-weight basic solutes in biologicalsamples. J. Microcol. Sep., 1994, 6, 107-113.
69. Hirokawa, T.; Watanabe, K.; Yokota, Y.; Kiso, Y. Bidirectionalisotachophoresis. 1. Verification of bidirectional isotachophoresisand simultaneous determination of anionic and cationic components. J. Chromatogr., 1993, 633, 251-259.
70. Thormann, W.; Arn, D.; Schumacher, E. Bidirectional analyticalisotachophoresis - simultaneous determination of anionic and cationicboundaries. Electrophoresis, 2008, 6, 10-18.
71. Kazarian, A.A.; Hilder, E.F.; Breadmore, M.C. Utilisation of pHstacking in conjunction with a highly absorbing chromophore, 5-aminofluorescein, to improve the sensitivity of capillary electrophoresisfor carbohydrate analysis. J. Chromatogr. A, 2008, 1200, 84-91.
72. Koval, D.; Jiraskova, J.; Strisovsky, K.; Konvalinka, J.; Kasicka, V. Capillary electrophoresis method for determination of D-serine andits application for monitoring of serine racemase activity. Electrophoresis, 2006, 27, 2558-2566.
73. Lamari, F.N.; Kuhn, R.; Karamanos, N.K. Derivatization of carbohydratesfor chromatographic, electrophoretic and mass spectrometricstructure analysis. J. Chromatogr. B, 2003, 793, 15-36.
74. Vogel, M.; Büldt, A.; Karst, U. Hydrazine reagents as derivatizingagents in environmental analysis - a critical review. Fresenius J. Anal. Chem., 2000, 366, 781-791.
75. Dabek-Zlotorzynska, E.; Lai, E.P.C. Separation of carbonyl 2, 4-dinitrophenylhydrazones by capillary electrochromatography withdiode array detection. J. Chromatogr. A, 1999, 853, 487-496.
76. Zhang, L.H.; Zhang, Y.K.; Zhu, J.; Zou, H.F. Fast analysis of capillaryelectrochromatography with non-porous ODS as the stationaryphase. Anal. Lett., 1999, 32, 2679-2690.
77. Zhao, S.L.; Dai, T.Y.; Liu, Z.; Wei, F.S.; Zou, H.F.; Xu, X.B. Determinationof lower aliphatic carbonyl compounds in stack gas astheir 2, 4-dinitrophenylhydrazones by micellar electrokinetic chromatography. Chemosphere, 1997, 35, 2131-2136.
78. Andrighetto, P.; Carofiglio, T.; Fornasier, R.; Tonellato, U. Capillaryelectrophoresis behavior of water-soluble anionic porphyrinsin the presence of beta-cyclodextrin and its O-methylated derivatives. Electrophoresis, 2000, 21, 619-626.
79. Kalný, D.; Albrecht-Gary, A.M.; Havel, J. Highly sensitive methodfor palladium(II) determination as a porphyrinato complex by capillaryzone electrophoresis. Anal. Chim. Acta, 2001, 439, 101-105.
80. Pyrzynska, K.; Kilian, K. Application of cyclodextrins as modifiersin electrophoretic separation of metalloporphyrins. J. Sep. Sci., 2006, 29, 282-287.
81. Tabata, M.; Suenaga, K. Different kinetic-behavior of zinc(II), cadmium(II), and lead(II) porphyrins in the ligand-substitution reactionwith ethylenediaminetetraacetic acid. Bull. Chem. Soc. Jpn., 1991, 64, 469-475.
82. Andrighetto, P.; Carofiglio, T.; Fornasier, R.; Tonellato, U. Ahighly sensitive method for the analysis of nitrite ions by capillaryzone electrophoresis using water-soluble aminophenylporphyrinderivative as chromogenic reagent. Electrophoresis, 2000, 21, 2384-2389.
83. He, X.L.; Wang, Y.Q.; Ling, K.Q. 5-methyl-2-[3-(4-phenylthiazol-2-yl)triazenyl]benzenesulfonic acid as a chromogenic reagent of Ncetylpyridiniumchloride - Synthesis, mechanism and analytical application. Talanta, 2008, 74, 821-830.
84. Liu, B.F.; Liu, L.B.; Cheng, J.K. Analysis of metal complexes inthe presence of mixed ion pairing additives in capillary electrophoresis. J. Chromatogr. A, 1999, 848, 473-484.
85. Liu, B.F.; Liu, L.B.; Chen, H.; Cheng, J.K. Analysis of metal complexesby capillary electrophoresis - Effect of organic additives onseparation of highly hydrophobic complexes. Anal. Chim. Acta, 2001, 434, 309-313.
86. Hardy, S.; Jones, P.; Riviello, J.M.; Avdalovic, N. Construction andinvestigation of a post-capillary reactor for trace metal analysis bycapillary electrophoresis. J. Chromatogr. A, 1999, 834, 309-320.
87. Chen, Z.L.; Naidu, R. On-column complexation capillary electrophoreticseparation of Fe2+ and Fe3+ using 2, 6-pyridinedicarboxylicacid coupled with large-volume sample stacking. J. Chromatogr. A, 2004, 1023, 151-157.
88. Naujalis, E.; Padarauskas, A. Development of capillary electrophoresisfor the determination of metal ions using mixed partial andcomplete complexation techniques. J. Chromatogr. A, 2002, 977, 135-142.
89. Priego-Capote, F.; Luque de Castro, M.D. Speciation of chromiumby in-capillary derivatization and electrophoretically mediated microanalysis. J. Chromatogr. A, 2006, 1113, 244-250.
90. Wang, M.; Lin, J.M.; Qu, F.; Shan, X.Q.; Chen, Z.L. On-capillarycomplexation of metal ions with 4-(2-thiazolylazo)resorcinol incapillary electrophoresis. J. Chromatogr. A, 2004, 1029, 249-254.
91. Yang, W.P.; Zhang, Z.J.; Deng, W. Speciation of chromium by incapillaryreaction and capillary electrophoresis with chemiluminescencedetection. J. Chromatogr. A, 2003, 1014, 203-214.
92. Bardelmeijer, H.A.; Lingeman, H.; de Ruiter, C.; Underberg, W.J.M. Derivatization in capillary electrophoresis. J. Chromatogr.A, 1998, 807, 3-26.
93. Zhu, R.H.; Kok, W.T. Post-column derivatization for fluorescenceand chemiluminescence detection in capillary electrophoresis. J. Pharm. Biomed. Anal., 1998, 17, 985-999.
94. Quirino, J.P.; Terabe, S. Sweeping of analyte zones in electrokineticchromatography. Anal. Chem., 1999, 71, 1638-1644.
95. Aranas, A.T.; Guidote, A.M.; Quirino, J.P. Sweeping and new onlinesample preconcentration techniques in capillary electrophoresis. Anal. Bioanal. Chem., 2009, 394, 175-185.
96. Palmer, J.; Munro, N.J.; Landers, J.P. A universal concept forstacking neutral analytes in micellar capillary electrophoresis. Anal. Chem., 1999, 71, 1679-1687.
97. Palmer, J.; Landers, J.P. Stacking neutral analytes in capillaryelectrokinetic chromatography with high-salt sample matrixes. Anal. Chem., 2000, 72, 1941-1943.
98. Palmer, J.; Burgi, D.S.; Munro, N.J.; Landers, J.P. Electrokineticinjection for stacking neutral analytes in capillary and microchipelectrophoresis. Anal. Chem., 2001, 73, 725-731.
99. Strein, T.G.; Morris, D.; Palmer, J.; Landers, J.P. Discontinuouselectrophoretic stacking system for cholate-based electrokineticchromatographic separation of 8-hydroxy-2 '-deoxyguanosine fromunmodified deoxynucleosides. J. Chromatogr. B, 2001, 763, 71-78.
100. Zhang, J.H.; Wu, X.P.; Zhang, W.; Xu, L.J.; Chen, G.N. A sweeping-micellar electrokinetic chromatography method for direct detectionof some aromatic amines in water samples. Electrophoresis, 2008, 29, 796-802.
101. Nunez, O.; Kim, J.B.; Moyano, E.; Galceran, M.T.; Terabe, S. Analysis of the herbicides paraquat, diquat and difenzoquat indrinking water by micellar electrokinetic chromatography usingsweeping and cation selective exhaustive injection. J. Chromatogr.A, 2002, 961, 65-75.
102. Gavenda, A.; Sevcik, J.; Psotová, J.; Bednar, P.; Bartak, P.; Adamovský, P.; Simánek, V. Determination of anthracycline antibioticsdoxorubicin and daunorubicin by capillary electrophoresiswith UV absorption detection. Electrophoresis, 2001, 22, 2782-2785.
103. Huang, H.M.; Lin, C.H. Methanol plug assisted sweeping-micellarelectrokinetic chromatography for the determination of dopaminein urine by violet light emitting diode-induced fluorescence detection. J. Chromatogr. B, 2005, 816, 113-119.
104. Lin, Y.H.; Li, J.H.; Ko, W.K.; Wu, S.M. Direct and sensitiveanalysis of methamphetamine, ketamine, morphine and codeine inhuman urine by cation-selective exhaustive injection and sweepingmicellar electrokinetic chromatography. J. Chromatogr. A, 2006, 1130, 281-286.
105. Quirino, J.P.; Kim, J.B.; Terabe, S. Sweeping: concentrationmechanism and applications to high-sensitivity analysis in capillaryelectrophoresis. J. Chromatogr. A, 2002, 965, 357-373.
106. Aebersold, R.; Morrison, H.D. Analysis of dilute peptide samplesby capillary zone electrophoresis. J. Chromatogr., 1990, 516, 79-88.
107. Kim, J.B.; Terabe, S. On-line sample preconcentration techniquesin micellar electrokinetic chromatography. J. Pharm. Biomed. Anal., 2003, 30, 1625-1643.
108. Nesbitt, C.A.; Lo, J.T.M.; Yeung, K.K.C. Over 1000-fold proteinpreconcentration for microliter-volume samples at a pH junctionusing capillary electrophoresis. J. Chromatogr. A, 2005, 1073, 175-180.
109. Britz-McKibbin, P.; Markuszewski, M.J.; Iyanagi, T.; Matsuda, K.; Nishioka, T.; Terabe, S. Picomolar analysis of flavins in biologicalsamples by dynamic pH junction-sweeping capillary electrophoresiswith laser-induced fluorescence detection. Anal. Biochem., 2003, 313, 89-96.
110. Britz-McKibbin, P.; Nishioka, T.; Terabe, S. Sensitive and highthroughputanalyses of purine metabolites by dynamic pH junctionmultiplexed capillary electrophoresis: A new tool for metabolomicstudies. Anal. Sci., 2003, 19, 99-104.
111. Tsai, C.H.; Lin, J.D.; Lin, C.H. Optimization of the separation ofmalachite green in water by capillary electrophoresis Raman spectroscopy(CE-RS) based on the stacking and sweeping modes. Talanta, 2007, 72, 368-372.
112. Ptolemy, A.S.; Britz-McKibbin, P. New advances in on-line samplepreconcentration by capillary electrophoresis using dynamic pHjunction. Analyst, 2008, 133, 1643-1648.
113. Park, S.; Lunte, C.E. On-column sample concentration of highionic-strength samples in capillary electrophoresis. J. Microcol. Sep., 1998, 10, 511-517.
114. Hadwiger, M.E.; Torchia, S.R.; Park, S.; Biggin, M.E.; Lunte, C.E. Optimization of the separation and detection of the enantiomers ofisoproterenol in microdialysis samples by cyclodextrin-modifiedcapillary electrophoresis using electrochemical detection. J. Chromatogr.B, 1996, 681, 241-249.
115. Xiong, Y.; Park, S.R.; Swerdlow, H. Base stacking: pH mediatedon-column sample concentration for capillary DNA sequencing. Anal. Chem., 1998, 70, 3605-3611.
116. Zhao, Y.; Lunte, C.E. pH mediated field amplification on-columnpreconcentration of anions in physiological samples for capillaryelectrophoresis. Anal. Chem., 1999, 71, 3985-3991.
117. Hirokawa, T.; Okamoto, H.; Gas, B. High-sensitive capillary zoneelectrophoresis analysis by electrokinetic injection with transientisotachophoretic preconcentration: Electrokinetic supercharging. Electrophoresis, 2003, 24, 498-504.
118. Xu, Z.Q.; Ando, T.; Nishine, T.; Arai, A.; Hirokawa, T. Electrokineticsupercharging preconcentration and microchip gel electrophoreticseparation of sodium dodecyl sulfate-protein complexes. Electrophoresis, 2003, 24, 3821-3827.
119. Xu, Z.Q.; Nishine, T.; Arai, A.; Hirokawa, T. Performance of electrokineticsupercharging for high-sensitivity detection of DNAfragments in chip gel electrophoresis. Electrophoresis, 2004, 25, 3875-3881.
120. Busnel, J.M.; Lion, N.; Girault, H.H. Electrokinetic superchargingfor highly efficient peptide preconcentration in capillary zone electrophoresis. Electrophoresis, 2008, 29, 1565-1572.
121. Dawod, M.; Breadmore, M.C.; Guijt, R.M.; Haddad, P.R. Electrokineticsupercharging for on-line preconcentration of seven nonsteroidalanti-inflammatory drugs in water samples. J. Chromatogr.A, 2008, 1189, 278-284.
122. Hirokawa, T.; Takayama, Y.; Arai, A.; Xu, Z.Q. Study of a novelsample injection method (floating electrokinetic supercharging) forhigh-performance microchip electrophoresis of DNA fragments. Electrophoresis, 2008, 29, 1829-1835.
123. Urbanek, M.; Delaunay, N.; Miche, R.; Varenne, A.; Gareil, P. Analysis of sub-ppb levels of Fe(II), Co(II), and Ni(II) by electrokineticsupercharging CZE separation, and preconcentration, incapillaryderivatization. Electrophoresis, 2007, 28, 3767-3776.
124. Xu, Z.Q.; Timerbaev, A.R.; Hirokawa, T. High-sensitivity capillaryand microchip electrophoresis using electrokinetic superchargingpreconcentration-Insight into stacking mechanism via computermodeling. J. Chromatogr. A, 2009, 1216, 660-670.
125. Hernandez, L.; Guzman, N.A.; Hoebel, B.G. Bidirectional microdialysisinvivo shows differential dopaminergic potency of cocaine, procaine and lidocaine in the nucleus-accumbens using capillaryelectrophoresis for calibration of drug outward diffusion. Psychopharmacology, 1991, 105, 264-268.
126. Chen, H.; Yu, Y.; Xia, Z.; Tang, S.; Mu, X.; Long, S. The fabricationand evaluation of inline coupling of microdialysis with capillaryelectrophoresis and its application in the determination ofblood glucose. Electrophoresis, 2006, 27, 4182-4187.
127. Thompson, J.E.; Vickroy, T.W.; Kennedy, R.T. Rapid determinationof aspartate enantiomers in tissue samples by microdialysiscoupled on-line with capillary electrophoresis. Anal. Chem., 1999, 71, 2379-2384.
128. Ciriacks, C.M.; Bowser, M.T. Monitoring D-serine dynamics in therat brain using online microdialysis-capillary electrophoresis. Anal. Chem., 2004, 76, 6582-6587.
129. Klinker, C.C.; Bowser, M.T. 4-fluoro-7-nitro-2, 1, 3-benzoxadiazoleas a fluorogenic labeling reagent for the in vivo analysis of aminoacid neurotransmitters using online microdialysis-capillary electrophoresis. Anal. Chem., 2007, 79, 8747-8754.
130. Ruiz-Jiménez, J.; Luque de Castro, M.D. Coupling microdialysis tocapillary electrophoresis. Trends Anal. Chem., 2006, 25, 563-571.
131. Tseng, W.C.; Sun, Y.C.; Lee, C.F.; Chen, B.H.; Yang, M.H.; Huang, Y.L. On-line microdialysis sampling coupled with flameatomic absorption spectrometry for continuous in vivo monitoringof diffusible magnesium in the blood of living animals. Talanta, 2005, 66, 740-745.
132. Fang, H.F.; Liu, M.M.; Zeng, Z.R. Solid-phase microextractioncoupled with capillary electrophoresis to determine ephedrine derivativesin water and urine using a sol-gel derived butyl methacrylate/silicone fiber. Talanta, 2006, 68, 979-986.
133. Wei, F.; Fan, Y.; Zhang, M.; Feng, Y.Q. Poly(methacrylic acidethyleneglycol dimethacrylate) monolith in-tube solid-phase microextractionapplied to simultaneous analysis of some amphetaminederivatives in urine by capillary zone electrophoresis. Electrophoresis, 2005, 26, 3141-3150.
134. Zhou, X.W.; Li, X.J.; Zeng, Z.R. Solid-phase microextractioncoupled with capillary electrophoresis for the determination of propranololenantiomers in urine using a sol-gel derived calix[4]arenefiber. J. Chromatogr. A, 2006, 1104, 359-365.
135. Hernández-Borges, J.; Rodríguez-Delgado, M.A.; García-Montelongo, F.J.; Cifuentes, A. Highly sensitive analysis of multiplepesticides in foods combining solid-phase microextraction, capillaryelectrophoresis-mass spectrometry and chemometrics. Electrophoresis, 2004, 25, 2065-2076.
136. Kumar, A.; Gaurav, V.; Malik, A.K.; Tewary, D.K.; Singh, B. Areview on development of solid phase microextraction fibers bysol-gel methods and their applications. Anal. Chim. Acta, 2008, 610, 1-14.
137. Vas, G.; Vekey, K. Solid-phase microextraction: a powerful samplepreparation tool prior to mass spectrometric analysis. J. Mass Spectrom., 2004, 39, 233-54.
138. Guzman, N.A. Improved solid-phase microextraction device foruse in on-line immunoaffinity capillary electrophoresis. Electrophoresis, 2003, 24, 1843-1851.
139. Liu, Z.; Pawliszyn, J. Microdialysis hollow fiber as a macromoleculetrap for on-line coupling of solid phase microextraction andcapillary electrophoresis. Analyst, 2006, 131, 522-528.
140. Santos, B.; Simonet, B.M.; Rios, A.; Valcárcel, M. On-line couplingof solid-phase microextraction to commercial CE-MS equipment. Electrophoresis, 2007, 28, 1312-1318.
141. Whang, C.W.; Pawliszyn, J. Solid phase microextraction coupledto capillary electrophoresis. Anal. Commun., 1998, 35, 353-356.
142. Chen, Y.; Guo, Z.P.; Wang, X.Y.; Qiu, C.G. Sample preparation. J. Chromatogr. A, 2008, 1184, 191-219.
143. Oleschuk, R.D.; Shultz-Lockyear, L.L.; Ning, Y.; Harrison, D.J. Trapping of bead-based reagents within microfluidic systems: Onchipsolid-phase extraction and electrochromatography. Anal. Chem., 2000, 72, 585-590.
144. Xie, B.; Mecklenburg, M.; Danielsson, B.; Ohman, O.; Norlin, P.; Winquist, F. Development of an integrated thermal biosensor forthe simultaneous determiantion of multiple analytes. Analyst, 1995, 120, 155-160.
145. Basheer, C.; Wang, H.J.; Jayaraman, A.; Valiyaveettil, S.; Lee, H.K. Polymer-coated hollow fiber microextraction combined withon-column stacking in capillary electrophoresis. J. Chromatogr. A, 2008, 1128, 267-272.
146. Li, P.J.; Duan, J.; Hu, B. High-sensitivity capillary electrophoresisfor speciation of organomercury in biological samples using hollowfiber-based liquid-liquid-liquid microextraction combined with onlinepreconcentration by large-volume sample stacking. Electrophoresis, 2008, 29, 3081-3089.
147. Nozal, L.; Arce, L.; Simonet, B.M.; Rios, A.; Valcárcel, M. In-lineliquid-phase microextraction for selective enrichment and directelectrophoretic analysis of acidic drugs. Electrophoresis, 2007, 28, 3284-3289.
148. Zhu, L.; Tu, C.; Lee, H.K. Liquid-phase microextraction of phenoliccompounds combined with on-line preconcentration by fieldamplifiedsample injection at low pH in micellar electrokineticchromatography. Anal. Chem., 2001, 73, 5655-5660.
149. Buskov, S.; Moller, P.; Sorensen, H.; Sorensen, J.C.; Sorensen, S. Determination of vitamins in food based on supercritical fluid extractionprior to micellar electrokinetic capillary chromatographicanalyses of individual vitamins. J. Chromatogr. A, 1998, 802, 233-241.
150. Mardones, C.; Ríos, A.; Valcárcel, M. Automatic on-line couplingof supercritical fluid extraction and capillary electrophoresis. Anal. Chem., 2000, 72, 5736-5739.
151. Halasz, A.; Groom, C.; Zhou, E.; Paquet, L.; Beaulieu, C.; Deschamps, S.; Corriveau, A.; Thiboutot, S.; Ampleman, G.; Dubois, C.; Hawari, J. Detection of explosives and their degradationproducts in soil environments. J. Chromatogr. A, 2002, 963, 411-418.
152. Vaher, M.; Koel, M. Separation of polyphenolic compounds extractedfrom plant matrices using capillary electrophoresis. J. Chromatogr. A, 2003, 990, 225-230.
153. Miura, J.; Ishii, H.; Watanabe, H. Extraction and separation ofnickel chelate of 1-(2-thiazolylazo)-2-naphthol in nonionic surfactantsolution. Bunseki Kagaku, 1976, 25, 808-809.
154. Luconi, M.O.; Olsina, R.A.; Fernandez, L.P.; Silva, M.F. Determinationof lead in human saliva by combined cloud point extractioncapillaryzone electrophoresis with indirect UV detection. J. HazardMater. B, 2006, 128, 240-246.
155. Tang, A.N.; Jiang, D.Q.; Yan, X.P. Cloud point extraction preconcentrationfor capillary electrophoresis of metal ions. Anal. Chim. Acta, 2004, 507, 199-204.
156. Carabias-Martínez, R.; Rodríguez-Gonzalo, E.; Moreno-Cordero, B.; Pérez-Pavón, J.L.; García-Pinto, C.; Fernández Laespada, E. Surfactant cloud point extraction and preconcentration of organiccompounds prior to chromatography and capillary electrophoresis. J. Chromatogr. A, 2000, 902, 251-265.
157. Zhu, X.S.; Zhu, X.H.; Hu, Y.Y.; Yu, S.H.; Wang, B.S. Cloud pointextraction of serum albumin and its spectrophotometric determinationin serum samples. Anal. Lett., 2006, 39, 1853-1864.
158. Carabias-Martínez, R.; Rodríguez-Gonzalo, E.; Dominguez-Alvarez, J.; Pinto, C.G.; Hernandez-Mendez, J. Prediction of thebehaviour of organic pollutants using cloud point extraction. J. Chromatogr. A, 2003, 1005, 23-34.
159. Sikalos, T.I.; Paleologos, E.K. Cloud point extraction coupled withmicrowave or ultrasonic assisted back extraction as a preconcentrationstep prior to gas chromatography. Anal. Chem., 2005, 77, 2544-2549.
160. Hinze, W.L.; Pramauro, E. A critical-review of surfactant-mediatedphase separations (cloud-point extractions) - Theory and applications. CRC Crit. Rev. Anal. Chem., 2008, 24, 133-177.
161. Quina, F.H.; Hinze, W.L. Surfactant-mediated cloud point extractions:An environmentally benign alternative separation approach. Ind. Eng. Chem. Res., 1999, 38, 4150-4168.
162. Sirimanne, S.R.; Barr, J.R.; Patterson, D.G. Cloud-point extractionand capillary electrochromatography: An approach for the analysisof selected environmental toxicants in spiked human serum. J. Microcol. Sep., 1999, 11, 109-116.
163. Baltussen, E.; Sandra, P.; David, F.; Cramers, C. Stir bar sorptiveextraction (SBSE), a novel extraction technique for aqueous samples:Theory and principles. J. Microcolumn Sep., 1999, 11, 737-747.
164. Baltussen, E.; Cramers, C.A.; Sandra, P.J.F. Sorptive sample preparation - a review. Anal. Bioanal. Chem., 2002, 373, 3-22.
165. De Villiers, A.; Vanhoenacker, G.; Lynen, F.; Sandra, P. Stir barsorptive extraction-liquid desorption applied to the analysis of hopderivedbitter acids in beer by micellar electrokinetic chromatography. Electrophoresis, 2004, 25, 664-669.
166. Juan-García, A.; Pico, Y.; Font, G. Capillary electrophoresis foranalyzing pesticides in fruits and vegetables using solid-phase extractionand stir-bar sorptive extraction. J. Chromatogr. A, 2005, 1073, 229-236.
167. Palmarsdottir, S.; Thordarson, E.; Edholm, L.E.; Jonsson, J.A.; Mathiasson, L. Miniaturized supported liquid membrane device forselective on-line enrichment of basic drugs in plasma combinedwith capillary zone electrophoresis. Anal. Chem., 1997, 69, 1732-1737.
168. Pedersen-Bjergaard, S.; Rasmussen, K.E. Liquid-liquid-liquidmicroextraction for sample preparation of biological fluids prior tocapillary electrophoresis. Anal. Chem., 1999, 71, 2650-2656.