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Pitkänen EM, Sirén HMM. Capillary zone electrophoresis of lipoarabinomannan by multi-layered concentration. J Sep Sci 2021; 45:945-959. [PMID: 34932878 DOI: 10.1002/jssc.202100357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 11/24/2021] [Accepted: 12/09/2021] [Indexed: 11/10/2022]
Abstract
The present paper describes a capillary zone electrophoresis method which relies on a multi-layered water-alkali solvent stacking with on-line ionization to enhance detection of mannose, arabinose, and their oligosaccharides, which are used as the migration profile standards but are also the distinctive structural components of lipoarabinomannan. Lipoarabinomannan is detected in patients having tuberculosis. The CE method with ionization of the whole saccharides without degradation in alkaline solution inside the capillary is based structural deprotonation of the molecules under ultrahigh pH conditions. The validation of the CE parameters revealed that the 15-fold electrolyte - water -injection plug allowed detection of one third lower concentrations than detected without on-line concentration. For the first time, the better detectability was seen especially for highly polymerized, but otherwise poorly ionized, arabino-octaose. The applicability of the method for detecting whole large biological saccharide complexes was confirmed by the glycolipid lipoarabinomannan. For the first time also, the migration of the indestructible lipoarabinomannan was detected together with oligosaccharides used representing the capping units, namely mannose, mannobiose and mannotriose. The myo-inositol-phosphate-lipid unit was seen to migrate separately from the arabinomannan, since it was hydrolyzed from one lipoarabinomannan product under alkaline conditions in CE. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Eeva Marja Pitkänen
- Department of Chemistry, University of Helsinki, PO Box 55, Helsinki, FI-00014, Finland
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2
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Combining capillary electromigration with molecular imprinting techniques towards an optimal separation and determination. Talanta 2021; 221:121546. [DOI: 10.1016/j.talanta.2020.121546] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/19/2020] [Accepted: 08/20/2020] [Indexed: 01/24/2023]
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3
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4-hydrazinobenzoic acid as a derivatizing agent for aldehyde analysis by HPLC-UV and CE-DAD. Talanta 2018; 187:113-119. [PMID: 29853022 DOI: 10.1016/j.talanta.2018.04.091] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/27/2018] [Accepted: 04/28/2018] [Indexed: 12/18/2022]
Abstract
Aldehydes are relevant analytes in a wide range of samples, in particular, food and beverages but also body fluids. Hydrazines can undergo nucleophilic addition with aldehydes or ketones giving origin to hydrazones (a group of stable imines) that can be suitably used in the identification of aldehydes. Herein, 4-hydrazinobenzoic acid (HBA) was, for the first time, used as the derivatizing agent in analytical methodologies using liquid chromatography aiming the determination of low-molecular aldehydes. The derivatization reaction was simultaneously performed along with the extraction process, using gas-diffusion microextraction (GDME), which resulted in a clean extract containing the HBA-aldehyde derivates. The corresponding formed imines were determined by both high-performance liquid chromatography (LC) with UV spectrophotometric detection (HPLC-UV) and capillary electrophoresis with diode array detection (CE-DAD). HBA showed to be a rather advantageous derivatization reagent due to its stability, relatively high solubility in water and other solvents, high selectivity and sensibility, reduced impurities, simple preparation steps and applicability to different separation and/or different detection techniques. Limits of detections (LODs) of the optimized methodologies (in terms of time and pH among other experimental variables) were all below 0.5 mg L-1, using both instrumental techniques. Furthermore, for the first time, the HBA-aldehyde derivatives were analyzed by LC with mass spectrometry (LC-MS), demonstrating the possibility of identification by MS of each compound. The developed methodologies were also successfully applied in the analysis of formaldehyde and acetaldehyde in several alcoholic beverages. This was also the first time GDME was combined with CE, showing that it can be a valuable sample preparation tool for electrophoresis, in particular by eliminating the interference of ions and inorganic constituents present in the samples.
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4
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Zhang Z, Sun L, Zhu G, Yan X, Dovichi NJ. Integrated strong cation-exchange hybrid monolith coupled with capillary zone electrophoresis and simultaneous dynamic pH junction for large-volume proteomic analysis by mass spectrometry. Talanta 2015; 138:117-122. [PMID: 25863379 PMCID: PMC4394190 DOI: 10.1016/j.talanta.2015.01.040] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 01/28/2015] [Accepted: 01/29/2015] [Indexed: 10/24/2022]
Abstract
A sulfonate-silica hybrid strong cation-exchange (SCX) monolith was synthesized at the proximal end of a capillary zone electrophoresis column and used for on-line solid-phase extraction (SPE) sample preconcentration. Sample was prepared in an acidic buffer and deposited onto the SCX-SPE monolith and eluted using a basic buffer. Electrophoresis was performed in an acidic buffer. This combination of buffers results in formation of a dynamic pH junction, which allows use of relatively large elution buffer volume while maintaining peak efficiency and resolution. All experiments were performed with a 50 µm ID capillary, a 1cm long SCX-SPE monolith, a 60cm long separation capillary, and a electrokinetically pumped nanospray interface. The volume of the capillary is 1.1 µL. By loading 21 µL of a 1×10(-7) M angiotensin II solution, an enrichment factor of 3000 compared to standard electrokinetic injection was achieved on this platform while retaining efficient electrophoretic performance (N=44,000 plates). The loading capacity of the sulfonate SCX hybrid monolith was determined to be ~15 pmol by frontal analysis with 10(-5) M angiotensin II. The system was also applied to the analysis of a 10(-4) mg/mL bovine serum albumin tryptic digest; the protein coverage was 12% and 11 peptides were identified. Finally, by loading 5.5 µL of a 10(-3) mg/mL E. coli digest, 109 proteins and 271 peptides were identified in a 20 min separation; the median separation efficiency generated by these peptides was 25,000 theoretical plates.
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Affiliation(s)
- Zhenbin Zhang
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Liangliang Sun
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Guijie Zhu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Xiaojing Yan
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Norman J Dovichi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 USA.
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Zhang Z, Yan X, Sun L, Zhu G, Dovichi NJ. Detachable strong cation exchange monolith, integrated with capillary zone electrophoresis and coupled with pH gradient elution, produces improved sensitivity and numbers of peptide identifications during bottom-up analysis of complex proteomes. Anal Chem 2015; 87:4572-7. [PMID: 25822566 DOI: 10.1021/acs.analchem.5b00789] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A detachable sulfonate-silica hybrid strong cation-exchange monolith was synthesized in a fused silica capillary, and used for solid phase extraction with online pH gradient elution during capillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) proteomic analysis. Tryptic digests were prepared in 50 mM formic acid and loaded onto the strong cation-exchange monolith. Fractions were eluted using a series of buffers with lower concentration but higher pH values than the 50 mM formic acid background electrolyte. This combination of elution and background electrolytes results in both sample stacking and formation of a dynamic pH junction and allows use of relatively large elution buffer volumes while maintaining reasonable peak efficiency and resolution. A series of five pH bumps were applied to elute E. coli tryptic peptides from the monolith, followed by analysis using CZE coupled to an LTQ-Orbitrap Velos mass spectrometer; 799 protein groups and 3381 peptides were identified from 50 ng of the digest in a 2.5 h analysis, which approaches the identification rate for this organism that was obtained with an Orbitrap Fusion. We attribute the improved numbers of peptide and protein identifications to the efficient fractionation by the online pH gradient elution, which decreased the complexity of the sample in each elution step and improved the signal intensity of low abundance peptides. We also performed a comparative analysis using a nanoACQUITY UltraPerformance LCH system. Similar numbers of protein and peptide identifications were produced by the two methods. Protein identifications showed significant overlap between the two methods, whereas peptide identifications were complementary.
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Affiliation(s)
- Zhenbin Zhang
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Xiaojing Yan
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Liangliang Sun
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Guijie Zhu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Norman J Dovichi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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Le ME, Vizel A, Hutterer KM. Automated sample preparation for CE-SDS. Electrophoresis 2013; 34:1369-74. [PMID: 23423814 DOI: 10.1002/elps.201200644] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 01/05/2013] [Accepted: 01/11/2013] [Indexed: 11/10/2022]
Abstract
Traditionally, CE with SDS (CE-SDS) places many restrictions on sample composition. Requirements include low salt content, known initial sample concentration, and a narrow window of final sample concentration. As these restrictions require buffer exchange for many sample types, sample preparation is often tedious and yields poor sample recoveries. To improve capacity and streamline sample preparation, an automated robotic platform was developed using the PhyNexus Micro-Extractor Automated Instrument (MEA) for both the reduced and nonreduced CE-SDS assays. This automated sample preparation normalizes sample concentration, removes salts and other contaminants, and adds the required CE-SDS reagents, essentially eliminating manual steps during sample preparation. Fc-fusion proteins and monoclonal antibodies were used in this work to demonstrate benefits of this approach when compared to the manual method. With optimized conditions, this application has demonstrated decreased analyst "hands on" time and reduced total assay time. Sample recovery greater than 90% can be achieved, regardless of initial composition and concentration of analyte.
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Affiliation(s)
- M Eleanor Le
- Process and Product Development, Amgen Inc, Thousand Oaks, CA, USA
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7
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Isotachophoresis-based sample preparation of cellulases in sugarcane juice using bovine serum albumin as a model protein. J Chromatogr A 2010; 1217:8026-31. [DOI: 10.1016/j.chroma.2010.08.047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 08/15/2010] [Accepted: 08/18/2010] [Indexed: 11/18/2022]
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8
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Mikus P, Maráková K. Advanced CE for chiral analysis of drugs, metabolites, and biomarkers in biological samples. Electrophoresis 2010; 30:2773-802. [PMID: 19653234 DOI: 10.1002/elps.200900173] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
An analysis of recent trends indicates that CE can show real advantages over chromatographic methods in ultratrace enantioselective determination of biologically active compounds in complex biological matrices. It is due to high separation efficiency and many applicable in-capillary electromigration effects in CE (countercurrent migration, stacking effects) enhancing significantly (enantio)separability and enabling effective sample preparation (preconcentration, purification, analyte derivatization). Other possible on-line combinations of CE, such as column coupled CE-CE techniques and implementation of nonelectrophoretic techniques (extraction, membrane filtration, flow injection) into CE, offer additional approaches for highly effective sample preparation and separation. CE matured to a highly flexible and compatible technique enabling its hyphenation with powerful detection systems allowing extremely sensitive detection (e.g. LIF) and/or structural characterization of analytes (e.g. MS). Within the last decade, more as well as less conventional analytical on-line approaches have been effectively utilized in this field and their practical potentialities are demonstrated on many new application examples in this article. Here, three basic areas of (enantioselective) drug bioanalysis are highlighted and supported by a brief theoretical description of each individual approach in a compact review structure (to create integrated view on the topic), including (i) progressive enantioseparation approaches and new enantioselective agents, (ii) in-capillary sample preparation (preconcentration, purification, derivatization), and (iii) detection possibilities related to enhanced sensitivity and structural characterization.
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Affiliation(s)
- Peter Mikus
- Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy, Comenius University, Bratislava, Slovak Republic.
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9
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Wei F, Fan J, Zheng MM, Feng YQ. Combining poly (methacrylic acid-co-ethylene glycol dimethacrylate) monolith microextraction and octadecyl phosphonic acid-modified zirconia-coated CEC with field-enhanced sample injection for analysis of antidepressants in human plasma and urine. Electrophoresis 2010; 31:714-23. [DOI: 10.1002/elps.200900425] [Citation(s) in RCA: 28] [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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10
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Xie HY, He YZ, Gan WE, Fu GN, Li L, Han F, Gao Y. On-column liquid–liquid–liquid microextraction coupled with base stacking as a dual preconcentration method for capillary zone electrophoresis. J Chromatogr A 2009; 1216:3353-9. [DOI: 10.1016/j.chroma.2009.01.070] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2008] [Revised: 01/17/2009] [Accepted: 01/23/2009] [Indexed: 10/21/2022]
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11
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García-Pérez I, Vallejo M, García A, Legido-Quigley C, Barbas C. Metabolic fingerprinting with capillary electrophoresis. J Chromatogr A 2008; 1204:130-9. [DOI: 10.1016/j.chroma.2008.07.025] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Revised: 07/01/2008] [Accepted: 07/08/2008] [Indexed: 10/21/2022]
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12
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Puig P, Tempels FWA, Somsen GW, de Jong GJ, Borrull F, Aguilar C, Calull M. Use of large-volume sample stacking in on-line solid-phase extraction-capillary electrophoresis for improved sensitivity. Electrophoresis 2008; 29:1339-46. [PMID: 18288781 DOI: 10.1002/elps.200700636] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We present a new system for the sensitive analysis of cephalosporins by CE using both on-line SPE and large-volume sample stacking (LVSS). Sample volumes of 250 muL were loaded onto the SPE microcolumn which was then desorbed with 426 nL of ACN. The SPE elution plug was injected into the CE system via an in-line valve interface filling approximately 60% of the volume of the separation capillary. Subsequently, LVSS was performed by applying a voltage of -5 kV, which resulted in the simultaneous removal of the elution solvent and the preconcentration of the analytes in a narrow zone. This way the amount of analyte loaded into the capillary could be considerably increased without serious loss of CE separation efficiency. LODs for cefoperazone and ceftiofur were in the ng/L range which represents an improvement of a factor of 8450 and 11 450 when compared with direct CE injection. The cephalosporin test compounds presented a good linear response (corrected peak area) between 0.5 and 10 mug/L with correlation coefficients higher than 0.995. The final method is compared with previously reported LVSS-CE and SPE-CE systems for the analysis of cephalosporins.
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Affiliation(s)
- Patricia Puig
- Department of Analytical Chemistry and Organic Chemistry, Faculty of Chemistry, Rovira i Virgili University, Tarragona, Spain.
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13
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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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14
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Wu XZ. Development of Novel In-Capillary Preconcentration Methods for Capillary Electrophoresis. BUNSEKI KAGAKU 2008. [DOI: 10.2116/bunsekikagaku.57.77] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Xing-Zheng Wu
- Department of Materials Science and Engineering, Graduate School of Engineering, University of Fukui
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15
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Sereda SV, Shpak AV, Pirogov AV, Shpigun OA. Electrostacking with ion flow superposition as a method of concentration in electrophoresis. RUSS J ELECTROCHEM+ 2007. [DOI: 10.1134/s1023193507120117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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Nozal L, Arce L, Simonet BM, Ríos A, Valcárcel M. In-line liquid-phase microextraction for selective enrichment and direct electrophoretic analysis of acidic drugs. Electrophoresis 2007; 28:3284-9. [PMID: 17703465 DOI: 10.1002/elps.200600468] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This work describes an efficient in-line extraction-preconcentration unit coupled to the electrophoretic capillary based on a liquid-phase microextraction (LPME) process, which can be directly assembled to the cartridge of the commercial CE equipment. The unit permits analyte extraction, preconcentration and electrophoretic separation to be automatically performed in the commercial CE equipment without the need for additional hardware or software. This new approach was usefully used for the separation and determination of nonsteroidal anti-inflammatory drugs in human urine permitting at least to analyze 30 consecutive real samples. The LODs were lower than 2 microg/L and the reproducibility, expressed as RSD, was 3.1% for the same unit and only 4.8% between different units.
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Affiliation(s)
- Leonor Nozal
- Department of Analytical Chemistry, University of Córdoba, Campus de Rabanales, Córdoba, Spain
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17
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Wei F, Zhang M, Feng YQ. Combining poly (methacrylic acid-co-ethylene glycol dimethacrylate) monolith microextraction and on-line pre-concentration-capillary electrophoresis for analysis of ephedrine and pseudoephedrine in human plasma and urine. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 850:38-44. [PMID: 17113366 DOI: 10.1016/j.jchromb.2006.10.060] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2006] [Revised: 09/20/2006] [Accepted: 10/31/2006] [Indexed: 11/20/2022]
Abstract
A method based on poly (methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-EGDMA) monolith microextraction (PMME) and field-enhanced sample injection (FESI) pre-concentration technique was proposed for sensitive capillary electrophoresis-ultraviolet (CE-UV) analysis of ephedrine (E) and pseudoephedrine (PE) in human plasma and urine. The PMME device consisted of a regular plastic syringe (1 mL), a poly (MAA-EGDMA) monolithic capillary (2 cm x 530 microm I.D.) and a plastic pinhead connecting the former two components seamlessly. The extraction was achieved by driving the sample solution through the monolithic capillary tube using a syringe pump, for the desorption step, an aliquot of organic solvent, which normally provided an excellent medium to ensure direct compatibility for FESI in CE, was injected via the monolithic capillary and collected into a vial for subsequent analysis by CZE. The best separation was achieved using a buffer composed of 0.1M phosphate electrolyte (pH 2.5) and 10% acetonitrile (v/v). The combination of both pre-concentration procedures allowed the detection limits of the analytes down to 5.3 ng/mL and 8.0 ng/mL in human plasma and urine, respectively. Excellent method of reproducibility was found over a linear range 50-5000 ng/mL in plasma and urine sample. Plasma and urine samples from volunteers receiving pseudoephedrine have also been successfully analysed.
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Affiliation(s)
- Fang Wei
- Department of Chemistry, Wuhan University, Wuhan 430072, PR China
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18
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Morales-Cid G, Simonet BM, Cárdenas S, Valcárcel M. On-capillary sample cleanup method for the electrophoretic determination of carbohydrates in juice samples. Electrophoresis 2007; 28:1557-63. [PMID: 17447235 DOI: 10.1002/elps.200600518] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
On many occasions, sample treatment is a critical step in electrophoretic analysis. As an alternative to batch procedures, in this work, a new strategy is presented with a view to develop an on-capillary sample cleanup method. This strategy is based on the partial filling of the capillary with carboxylated single-walled carbon nanotube (c-SWNT). The nanoparticles retain interferences from the matrix allowing the determination and quantification of carbohydrates (viz glucose, maltose and fructose). The precision of the method for the analysis of real samples ranged from 5.3 to 6.4%. The proposed method was compared with a method based on a batch filtration of the juice sample through diatomaceous earth and further electrophoretic determination. This method was also validated in this work. The RSD for this other method ranged from 5.1 to 6%. The results obtained by both methods were statistically comparable demonstrating the accuracy of the proposed methods and their effectiveness. Electrophoretic separation of carbohydrates was achieved using 200 mM borate solution as a buffer at pH 9.5 and applying 15 kV. During separation, the capillary temperature was kept constant at 40 degrees C. For the on-capillary cleanup method, a solution containing 50 mg/L of c-SWNTs prepared in 300 mM borate solution at pH 9.5 was introduced for 60 s into the capillary just before sample introduction. For the electrophoretic analysis of samples cleaned in batch with diatomaceous earth, it is also recommended to introduce into the capillary, just before the sample, a 300 mM borate solution as it enhances the sensitivity and electrophoretic resolution.
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Affiliation(s)
- Gabriel Morales-Cid
- Department of Analytical Chemistry, Marie Curie Building, Campus de Rabanales, University of Cordoba, Cordoba, Spain
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Zhang LH, Zhang CJ, Chen X, Feng YQ, Wu XZ. In-capillary solid-phase extraction-capillary electrophoresis for the determination of chlorophenols in water. Electrophoresis 2006; 27:3224-32. [PMID: 16865667 DOI: 10.1002/elps.200500700] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A novel CE method combined with SPE in a single capillary was developed for analysis of chlorophenols in water. A frit of 0.5 mm was first made by a sol-gel method, followed by packing a SPE sorbent in the inlet end of the capillary. Two phenol derivatives, 2,4-dichlorophenol and 2,4,5-trichlorophenol, were used as the model compounds. By loading sample solutions into the capillary, the two chlorophenols were extracted into the sorbent. They were desorbed by injecting only about 4 nL of methanol. Finally, the analytes were separated by conventional CE. The technique provided a concentration enhancement factor of over 4000-fold for both chlorophenols. The detection limits (S/N = 3) of 2,4-dichlorophenol and 2,4,5-trichlorophenol were determined to be 0.1 ng/mL and 0.07 ng/mL, respectively. For replicate analyses of 5 ng/mL of 2,4-dichlorophenol, within-day and between-day RSDs of migration time, peak height and peak area were in the range of 1.8-2.0%, 4.0-4.4% and 4.1-4.6%, respectively. The method shows wide linear range, acceptable reproducibility and excellent sensitivity, and it was applied to the analyses of spiked river water samples. The capillary packed with the SPE sorbents can be used for more than 400 runs without performance deterioration.
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Affiliation(s)
- Luo-Hong Zhang
- Department of Materials Science and Engineering, Faculty of Engineering, University of Fukui, Fukui, Japan
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21
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Nozal L, Arce L, Simonet BM, Ríos A, Valcárcel M. New supported liquid membrane-capillary electrophoresis in-line arrangement for direct selective analysis of complex samples. Electrophoresis 2006; 27:3075-85. [PMID: 16874840 DOI: 10.1002/elps.200500038] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
An in-line coupling of a micro-membrane extraction unit, based on supported liquid membrane, with commercially available capillary electrophoresis equipment is described. A main characteristic of this micro-membrane device, made from a simple Eppendorf tube, is that it permits the application of voltage in the acceptor solution to be applied during the extraction process. This has been shown as an alternative to enhance sensitivity, as the analytical signal achieved by applying 10 kV for 20 min was similar to that obtained without the application of voltage and with extraction time of 60 min. In addition, the design has been made permitting both in-line hydrodynamic and electrokinetic sample introduction into the electrophoretic capillary. The analytical potential of the proposed system has been demonstrated by the direct determination of nitroimidazoles from pig liver tissue. The high efficiency of the proposed system allowed the extraction and the determination of the analytes to be performed from a simple tissue homogenate obtained in water. The precision of the analysis of spiked samples, expressed in terms of relative standard deviation, was better than 4.8%.
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Affiliation(s)
- Leonor Nozal
- Department of Analytical Chemistry, University of Cordoba, Campus de Rabanales, E-14071 Cordoba, Spain
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22
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Sandra K, Lynen F, Devreese B, Van Beeumen J, Sandra P. On-column sample enrichment for the high-sensitivity sheath-flow CE-MS analysis of peptides. Anal Bioanal Chem 2006; 385:671-7. [PMID: 16741765 DOI: 10.1007/s00216-006-0461-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2006] [Accepted: 03/30/2006] [Indexed: 01/25/2023]
Abstract
A sample enrichment technique to increase sensitivity in capillary electrophoresis-mass spectrometry (CE-MS) is described. Peptides or glycopeptides are retained and concentrated on a short (3-5-mm) reversed-phase (C18) packed-bed situated in the fused-silica separation capillary and are subsequently released for electrophoretic separation by injection of an organic elutant. The concentration limits of detection are in the high picomolar range with a sheath-flow CE-MS interface.
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Affiliation(s)
- K Sandra
- Laboratory of Protein Biochemistry and Protein Engineering, Ghent University, K.L. Ledeganckstraat 35, 9000 Gent, Belgium
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Dabek-Zlotorzynska E, Celo V. Recent advances in capillary electrophoresis and capillary electrochromatography of pollutants. Electrophoresis 2006; 27:304-22. [PMID: 16315167 DOI: 10.1002/elps.200500547] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Recent advances in the CE and CEC separation, detection, and sample preparation methodologies applied to the determination of a variety of compounds having current or potential environmental relevance have been overviewed. The reviewed literature has illustrated the wide range of CE applications, indicating the continuing interest in CE and CEC in the environmental field.
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Affiliation(s)
- Ewa Dabek-Zlotorzynska
- Analysis and Air Quality Division, Environmental Technology Centre, Environment Canada, Ottawa, Ontario, Canada.
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Kasicka V. Recent developments in capillary electrophoresis and capillary electrochromatography of peptides. Electrophoresis 2006; 27:142-75. [PMID: 16307429 DOI: 10.1002/elps.200500527] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The article gives a comprehensive review on the recent developments in the applications of high-performance capillary electromigration methods, zone electrophoresis, isotachophoresis, isoelectric focusing, affinity electrophoresis, electrokinetic chromatography, and electrochromatography, to analysis, preparation, and physicochemical characterization of peptides. The article presents new approaches to the theoretical description and experimental verification of electromigration behavior of peptides, covers the methodological aspects of capillary electroseparations of peptides, such as rational selection of separation conditions, sample preparation, suppression of peptide adsorption, new developments in individual separation modes, and new designs of detection systems. Several types of applications of capillary electromigration methods to peptide analysis are presented: conventional qualitative and quantitative analysis, purity control, determination in biomatrices, monitoring of chemical and enzymatical reactions and physical changes, amino acid and sequence analysis, and peptide mapping of proteins. Some examples of micropreparative peptide separations are given and capabilities of capillary electromigration techniques to provide important physicochemical characteristics of peptides are demonstrated.
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Affiliation(s)
- Václav Kasicka
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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Zhang LH, Zhang CJ, Wu XZ. Isoelectric Focusing Sample Injection for Capillary Zone Electrophoresis in a Fused Silica Capillary. ANAL SCI 2006; 22:1039-41. [PMID: 16837761 DOI: 10.2116/analsci.22.1039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
An improvement has been made to couple isoelectric focusing (IEF) sample injection and capillary zone electrophoresis in an untreated fused silica capillary. Electroosmotic flow is efficiently prevented by simply using a rubber block at the outlet end of the capillary during IEF sample injection. The experimental conditions that affect the concentration effect are discussed. A concentration enhancement factor of over 100-fold can be easily obtained for two model proteins: lysozyme and ribonuclease A.
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Affiliation(s)
- Luo-Hong Zhang
- Department of Materials Science and Engineering, Faculty of Engineering, University of Fukui, Bunkyo 3-9-1. Fukui 910-8507, Japan
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Zhang M, Wei F, Zhang YF, Nie J, Feng YQ. Novel polymer monolith microextraction using a poly(methacrylic acid-ethylene glycol dimethacrylate) monolith and its application to simultaneous analysis of several angiotensin II receptor antagonists in human urine by capillary zone electrophoresis. J Chromatogr A 2006; 1102:294-301. [PMID: 16300774 DOI: 10.1016/j.chroma.2005.10.057] [Citation(s) in RCA: 173] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2005] [Revised: 10/15/2005] [Accepted: 10/27/2005] [Indexed: 11/25/2022]
Abstract
Novel polymer monolith microextraction (PMME) using a poly(methacrylic acid-ethylene glycol dimethacrylate) (poly(MAA-EGDMA)) monolith in conjunction with capillary zone electrophoresis (CZE) was developed for the determination of several angiotensin II receptor antagonists (ARA-IIs) in human urine. The extraction device consisted of a regular plastic syringe (1 mL), a poly(MAA-EGDMA) monolithic capillary (2 cm x 530 microm I.D.) and a plastic pinhead connecting the former two components seamlessly. The extraction was achieved by driving the sample solution through the monolithic capillary tube using a syringe infusion pump, and for the desorption step, an aliquot of organic solvent was injected via the monolithic capillary and collected into a vial for subsequent analysis by CZE. The best separation was realized at 25 kV using a buffer that consisted of 50% acetonitrile and 50% buffer solution (v/v) containing 10 mM disodium hydrogenphosphate (adjusted to pH 2.3 with 1M hydrochloric acid). The method was successfully applied to the determination of telmisartan (T), irbesartan (I) and losartan (L) in urine samples with candesartan (C) as internal standard, yielding the detection limit of 15-20 ng/mL. Close correlation coefficients (R>0.999) and excellent method reproducibility were obtained for all the analytes over a linear range of 0.08-3 microg/mL.
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Affiliation(s)
- Min Zhang
- Department of Chemistry, Wuhan University, Wuhan 430072, China
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Wu XZ, Umeda R. In-capillary preconcentration of proteins for capillary electrophoresis using a cellulose acetate-coated porous joint. Anal Bioanal Chem 2005; 382:848-52. [PMID: 15906013 DOI: 10.1007/s00216-005-3136-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2004] [Revised: 01/26/2005] [Accepted: 01/31/2005] [Indexed: 10/25/2022]
Abstract
This work describes the in-capillary preconcentration of proteins using a cellulose acetate-coated porous joint. The capillary wall near the inlet end of a capillary was made porous by HF etching. During the etching process, a voltage was applied across the capillary wall and the electric current across it was monitored. As the current passed through the capillary wall, it became porous. A solution of cellulose acetate in acetone was added to the etched porous joint. After the acetone was evaporated off, a cellulose acetate-coated porous joint was formed. To preconcentrate the protein ions, an electric voltage was applied between the inlet end of the capillary and the coated porous joint; the protein ions electromigrated to the porous joint but could not pass through it, while the buffer ions could pass easily through the joint. After allowing a certain amount of time for protein preconcentration, a separation voltage was applied across the two ends of the capillary, and normal capillary electrophoresis was carried out. The preconcentration factors for cytochrome c, lysozyme, ribonuclease, and chymotrypsinogen were 65, 155, 705, and 800, respectively. The cellulose acetate-coated porous joint was shown to be strong and stable over time, and was used to analyze trace proteins and macromolecules in biological samples.
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Affiliation(s)
- Xing-Zheng Wu
- Department of Materials Science and Engineering, Faculty of Engineering, Fukui University, Bunkyo 3-9-1, Fukui 910-8507, Japan.
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Wu XZ, Zhang LH, Onoda K. Isoelectric focusing sample injection for capillary electrophoresis of proteins. Electrophoresis 2005; 26:563-70. [PMID: 15690458 DOI: 10.1002/elps.200410028] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Carrier ampholyte-free isoelectric focusing (IEF) sample injection (concentration) for capillary electrophoresis (CE) is realized in a single capillary. A short section of porous capillary wall was made near the injection end of a capillary by HF etching. In the etching process, an electric voltage was applied across the etching capillary wall and electric current was monitored. When an electric current through the etching capillary was observed, the capillary wall became porous. The etched part was fixed in a vial, where NaOH solution with a certain concentration was added during the sample injection. The whole capillary was filled with pH 3.0 running buffer. The inlet end vial was filled with protein sample dissolved in the running buffer. An electric voltage was applied across the inlet end vial and etched porous wall. A neutralization reaction occurs at the boundary (interface) of the fronts of H+ and OH-. A pH step or sharp pH gradient exists across the boundary. When positive protein ions electromigrate to the boundary from the sample vial, they are isoelectricelly focused at points corresponding to their pH. After a certain period of concentration, a high voltage is applied across the whole capillary and a conventional CE is followed. An over 100-fold concentration factor has been easily obtained for three model proteins (bovine serum albumin, lysozyme, ribonuclease A). Furthermore, the IEF sample concentration and its dynamics have been visually observed with the whole-column imaging technique. Its merits and remaining problem have been discussed, too.
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Affiliation(s)
- Xing-Zheng Wu
- Department of Materials Scienceand Engineering, Faculty ofEngineering, Fukui University,Fukui, Japan.
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Ramos L, Ramos JJ, Brinkman UAT. Miniaturization in sample treatment for environmental analysis. Anal Bioanal Chem 2004; 381:119-40. [PMID: 15602622 DOI: 10.1007/s00216-004-2906-5] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2004] [Revised: 10/17/2004] [Accepted: 10/18/2004] [Indexed: 10/26/2022]
Abstract
The increasing demand for faster, more cost-effective and environmentally friendly analytical methods is a major incentive to improve the classical procedures used for sample treatment in environmental analysis. In most classical procedures, the use of rapid and powerful instrumental techniques for the final separation and detection of the analytes contrasts with the time-consuming and usually manual methods used for sample preparation, which slows down the total analytical process. The efforts made in this field in the past ten years have led to the adaptation of existing methods and the development of new techniques to save time and chemicals, and improve overall performance. One route has been to develop at-line or on-line and, frequently, automated systems. In these approaches, miniaturization has been a key factor in designing integrated analytical systems to provide higher sample throughput and/or unattended operation. Selected examples of novel developments in the field of miniaturized sample preparation for environmental analysis are used to evaluate the merits of the various techniques on the basis of published data on real-life analyses of trace-level organic pollutants. Perspectives and trends are briefly discussed.
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Affiliation(s)
- L Ramos
- Department of Instrumental Analysis and Environmental Chemistry, Institute of Organic Chemistry, CSIC, Juan de la Cierva 3, 28006 Madrid, Spain.
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Priego-Capote F, Luque de Castro MD. Dual injection capillary electrophoresis: Foundations and applications. Electrophoresis 2004; 25:4074-85. [PMID: 15597416 DOI: 10.1002/elps.200406135] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The state of the art of capillary electrophoresis (CE) approaches based on dual injection is here reported. Dual injection strategies have been proposed with three main objectives: (i) to provide information about reaction kinetics and/or related parameters, (ii) to perform in-capillary derivatization for improving separation and/or determination, (iii) to develop electrophoretic methods for the simultaneous analysis of anionic and cationic compounds. For the first two purposes, dual injection, which involves sample and reagent, can be realized either from the same end of the capillary (electrophoretically mediated microanalysis, EMMA) or from the two ends of the capillary (electroinjection analysis, EIA). The third objective, with dual injection of sample from the two ends of the capillary, takes advantage of moving cationic and anionic compounds with opposite directions. The foundations of each alternative, conditions necessary for working with them, restrictions, applications as well as perspectives are reviewed in order to establish the advantages, shortcomings, and convenience or no of their use in comparison to conventional CE.
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Macià A, Borrull F, Calull M, Aguilar C. Determination of some acidic drugs in surface and sewage treatment plant waters by capillary electrophoresis-electrospray ionization-mass spectrometry. Electrophoresis 2004; 25:3441-9. [PMID: 15490451 DOI: 10.1002/elps.200406067] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We describe an analytical method involving solid-phase extraction (SPE) and capillary zone electrophoresis-electrospray ionization-mass spectrometry (CZE-ESI-MS) for determining some pharmaceutical compounds - naproxen, clofibric acid and bezafibrate - in real water samples. The electrospray parameters were optimized to maximize sensitivity. When a mixed aqueous-organic solvent and CZE-ESI-MS were used to analyze these drugs in water samples, the capillary was coated with hexadimethrin bromide (HDB) to permanently reverse the EOF. The method was developed from off-line SPE-CZE-MS and was validated with surface water. The detection limits were 100 ng.L(-1) for all analytes. The method was applied to analyze water samples from the influent and effluent of a sewage treatment plant. A liquid-liquid extraction step was required before SPE, and the compounds studied were found, some of them between detection and quantification limits.
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Affiliation(s)
- Alba Macià
- Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, Tarragona, Spain
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Janos P. Analytical separations of lanthanides and actinides by capillary electrophoresis. Electrophoresis 2003; 24:1982-1992. [PMID: 12858369 DOI: 10.1002/elps.200305470] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The separation of lanthanide and actinide elements belongs to one of the most challenging tasks of the separation science, due to a great similarity in their physical and chemical properties. The electrophoretic separation can be accomplished in the presence of suitable complex-forming agents, from which alpha-hydroxyisobutyric acid (HIBA) has been used most often. In the most effective capillary electrophoretic mode--capillary zone electrophoresis (CZE)--a complete separation of lanthanide ions can be accomplished within a few minutes. Various electrophoretic methods can be relatively easily adopted for the determinations of individual lanthanide elements in certain kinds of technical materials, concentrates, precursors, etc., where the high speed and low costs of analysis characteristics of capillary electrophoresis (CE) may be advantageously exploited. Electrophoretic techniques may also be employed for speciation studies, especially for examinations of the behavior of actinides in the environment.
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Affiliation(s)
- Pavel Janos
- Faculty of Environmental Studies, University of Jan Evangelista Purkyne, Ustí nad Labem, Czech Republic.
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Wu XZ, Kasashima K, Sakai M. Capillary Electrophoresis of Small Anions in Complex Samples with a Hollow Fiber Sampling Inlet End. ANAL SCI 2003; 19:1541-3. [PMID: 14640455 DOI: 10.2116/analsci.19.1541] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A hollow fiber sampling inlet end of capillary electrophoresis (CE) for small ions in complex samples is described. A short piece of hollow fiber, which only permits small ions to pass through its wall, was directly connected to one end of a capillary. Small ions in complex samples were injected into the capillary through the hollow fiber by an electrokinetic method. The experimental results of CE for standard anion mixture solutions, river water, and milk samples show that the hollow fiber sampling inlet end is a simple and useful method for the CE of complex samples. Furthermore, it has been shown that the method can be used to study small anion changes during the milk storing process.
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Affiliation(s)
- Xing-Zheng Wu
- Department of Materials Science and Engineering, Faculty of Engineering, Fukui University, Bunkyo, Fukui 910-8507, Japan
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