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Gidlund MA, Molina RFS, Burger E. An improved high-performance liquid chromatography (HPLC) method for detection of variations in the hydroxyproline content of tissue homogenates from Paracoccidioides brasiliensis-infected mice. J Venom Anim Toxins Incl Trop Dis 2024; 30:e20230068. [PMID: 39055048 PMCID: PMC11270750 DOI: 10.1590/1678-9199-jvatitd-2023-0068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 05/25/2024] [Indexed: 07/27/2024] Open
Abstract
Background Paracoccidioidomycosis (PCM) is a severe granulomatous disease. The hallmark of this mycosis is fibrin degradation and granuloma formation as a result of a wound-healing process in the context of excessive inflammation. Therefore, as the content of collagen can be assessed by the methodology described in this manuscript, we propose that the content of hydroxyproline (HYP) be employed as a new and efficient measurement of granulomatous lesions developed. To estimate the level of HYP the major byproduct of the degradation process, we hypothesized that this simple and efficient technique could serve as a marker of disease severity. Methods Five B10.A female mice were infected with P. brasiliensis and, after 15 days, the omentum was removed, subjected to histopathological analysis or processed (i.e. deproteinized and derivatized), and further analyzed on a reverse phase HPLC using a C-18 column. The omentum of five uninfected controls was also collected and similarly analyzed. Results Infected mice showed numerous, disseminated paracoccidioidomycotic lesions, as well as marked collagen deposits, as observed in histopathologic analysis, and high levels of HYP. Normal uninfected mice showed no granulomas, little or no deposits of collagen fibers, and very low levels of HYP, as evaluated by HPLC. Our results show that the disease intensity as evaluated number and the morphology of the granulomatous lesions were correlated to the HYP levels using small tissue samples from the omentum, the main target organ of P. brasiliensis. Conclusions Here we propose an alternative methodology to follow disease evolution and, to some extent, fungal load in experimental P. brasiliensis infection and suggest its usefulness to other diseases with pronounced fibrin degradation.
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Affiliation(s)
- Magnus Ake Gidlund
- Department of Immunology, Institute of Biomedical Sciences (ICB),
University of São Paulo (USP), São Paulo, SP, Brazil
| | - Raphael Fagnani Sanchez Molina
- Department of Microbiology and Immunology, Institute of Biomedical
Sciences, Federal University of Alfenas, Alfenas, MG, Brazil
| | - Eva Burger
- Department of Microbiology and Immunology, Institute of Biomedical
Sciences, Federal University of Alfenas, Alfenas, MG, Brazil
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Yu YL, Shi MZ, Zhu SC, Cao J. Rapid stacking of amino acids in soybean and Dendrobium officinale by on-capillary sandwich derivatization in capillary electrophoresis. Food Res Int 2022; 162:112071. [DOI: 10.1016/j.foodres.2022.112071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 09/04/2022] [Accepted: 10/18/2022] [Indexed: 11/25/2022]
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3
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Chiral capillary electrophoresis with UV-excited fluorescence detection for the enantioselective analysis of 9-fluorenylmethoxycarbonyl-derivatized amino acids. Anal Bioanal Chem 2018; 410:4979-4990. [PMID: 29808298 PMCID: PMC6061710 DOI: 10.1007/s00216-018-1148-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/14/2018] [Accepted: 05/16/2018] [Indexed: 10/29/2022]
Abstract
The potential of capillary electrophoresis (CE) with ultraviolet (UV)-excited fluorescence detection for sensitive chiral analysis of amino acids (AAs) was investigated. DL-AAs were derivatized with 9-fluorenylmethoxycarbonyl chloride (FMOC)-Cl to allow their fluorescence detection and enhance enantioseparation. Fluorescence detection was achieved employing optical fibers, leading UV excitation light (< 300 nm) from a Xe-Hg lamp to the capillary window, and fluorescence emission to a spectrograph equipped with a charge-coupled device (CCD). Signal averaging over time and emission wavelength intervals was carried out to improve the signal-to-noise ratio of the FMOC-AAs. A background electrolyte (BGE) of 40 mM sodium tetraborate (pH 9.5), containing 15% isopropanol (v/v), 30 mM sodium dodecyl sulfate (SDS), and 30 mM β-cyclodextrin (β-CD), was found optimal for AA chemo- and enantioseparation. Enantioresolutions of 1.0 or higher were achieved for 16 proteinogenic DL-AAs. Limits of detection (LODs) were in the 10-100-nM range (injected concentration) for the D-AA enantiomers, except for FMOC-D-tryptophan (536 nM) which showed intramolecular fluorescence quenching. Linearity (R2 > 0.997) and repeatability for peak height (relative standard deviations (RSDs) < 7.0%; n = 5) and electrophoretic mobility (RSDs < 0.6%; n = 5) of individual AA enantiomers were established for chiral analysis of DL-AA mixtures. The applicability of the method was investigated by the analysis of cerebrospinal fluid (CSF). Next to L-AAs, endogenous levels of D-glutamine and D-aspartic acid could be measured in CSF revealing enantiomeric ratios of 0.35 and 19.6%, respectively. This indicates the method's potential for the analysis of low concentrations of D-AAs in presence of abundant L-AAs.
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4
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Denoroy L, Parrot S. Analysis of Amino Acids and Related Compounds by Capillary Electrophoresis. SEPARATION AND PURIFICATION REVIEWS 2016. [DOI: 10.1080/15422119.2016.1212378] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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5
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Passos HM, Cieslarova Z, Simionato AVC. CE-UV for the characterization of passion fruit juices provenance by amino acids profile with the aid of chemometric tools. Electrophoresis 2016; 37:1923-9. [PMID: 26800985 DOI: 10.1002/elps.201500483] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/21/2015] [Accepted: 01/05/2016] [Indexed: 11/08/2022]
Abstract
A separation method was developed in order to quantify free amino acids in passion fruit juices using CE-UV. A selective derivatization reaction with FMOC followed by MEKC analysis was chosen due to the highly interconnected mobilities of the analytes, enabling the separation of 22 amino acids by lipophilicity differences, as will be further discussed. To achieve such results, the method was optimized concerning BGE composition (concentrations, pH, and addition of organic modifier) and running conditions (temperature and applied voltage). The optimized running conditions were: a BGE composed by 60 mmol/L borate buffer at pH 10.1, 30 mmol/L SDS and 5 % methanol; running for 40 min at 23°C and 25 kV. The method was validated and applied on eight brands plus one fresh natural juice, detecting 12 amino acids. Quantification of six analytes combined with principal component analysis was capable to characterize different types of juices and showed potential to detect adulteration on industrial juices. Glutamic acid was found to be the most concentrated amino acid in all juices, exceeding 1 g/L in all samples and was also crucial for the correct classification of a natural juice, which presented a concentration of 22 g/L.
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Affiliation(s)
| | - Zuzana Cieslarova
- Institute of Chemistry, University of Campinas-Unicamp, Campinas, SP, Brazil
| | - Ana Valéria Colnaghi Simionato
- Institute of Chemistry, University of Campinas-Unicamp, Campinas, SP, Brazil.,National Institute of Science and Technology in Bioanalytics, Brazil
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6
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Chung TC, Li CT, Kou HS, Wu HL. High-Performance Liquid Chromatographic Analysis of Sarcosine as a Fluorescent Levofloxacin Derivative. J Chromatogr Sci 2015; 53:1310-5. [DOI: 10.1093/chromsci/bmv010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Indexed: 01/26/2023]
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7
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Song L, Guo Z, Chen Y. One-pot labeling-based capillary zone electrophoresis for separation of amino acid mixture and assay of biofluids. Anal Chim Acta 2011; 703:257-63. [DOI: 10.1016/j.aca.2011.07.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 07/18/2011] [Accepted: 07/24/2011] [Indexed: 11/28/2022]
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8
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Tseng HM, Barrett DA. Micellar electrokinetic biofluid analysis of biogenic amines using on-line sample concentration and UV laser-induced native fluorescence detection. J Chromatogr A 2009; 1216:3387-91. [DOI: 10.1016/j.chroma.2009.02.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Revised: 02/02/2009] [Accepted: 02/05/2009] [Indexed: 10/21/2022]
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9
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Issaq HJ. THIRTY-FIVE YEARS OF CAPILLARY ELECTROPHORESIS: ADVANCES AND PERSPECTIVES. J LIQ CHROMATOGR R T 2007. [DOI: 10.1081/jlc-120004015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Haleem J. Issaq
- a Analytical Chemistry Laboratory, SAIC-Frederick, Inc. , National Cancer Institute at Frederick , P.O.Box B, Frederick , MD , 21702 , U.S.A
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Possari R, Carvalhal RF, Mendes RK, Kubota LT. Electrochemical detection of cysteine in a flow system based on reductive desorption of thiols from gold. Anal Chim Acta 2006; 575:172-9. [PMID: 17723588 DOI: 10.1016/j.aca.2006.06.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Revised: 05/31/2006] [Accepted: 06/01/2006] [Indexed: 01/23/2023]
Abstract
A simple strategy for cysteine determination using flow-injection analysis with electrochemical detection is described. The approach is based on the chemisorptions reactions of the sulfur moiety of cysteine upon polycrystalline gold electrodes and its subsequent reductive desorption. The electrochemical measurements were accomplished by the application of differential pulse voltammetry (DPV) for the operational optimization and pulsed electrochemical detection (PED) in combination with flow-injection analysis for the electrochemical detection as time function. The electroactive species could be adsorbed in a potential level (0.1 V versus SCE), at other (-0.6 V versus SCE) occurs their reductive desorption from the electrode, while the analytical current is recorded simultaneously, and a third potential step is applied to the complete regeneration of the gold electrode surface (-1.3 V versus SCE). The linear response range was observed between 1.0 x 10(-6) and 6.0 x 10(-6) mol L(-1) with a good reproducibility (R.S.D.<3.2%) and sensitivity (1.1 microA/microM). The repeatability (a series of 27 continuous FIA peaks of 5. 0 micromol L(-1) of cysteine) was 3.8 % and the limit of detection was 5.0 x 10(-7) mol L(-1). The sample throughput was 23 samples per hour with a very high stability in its voltammetric response. The developed methodology was successfully used for the determination of cysteine in commercial supplementary food sample.
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Affiliation(s)
- Rodrigo Possari
- Instituto de Química, Universidade Estadual de Campinas-UNICAMP, CP 6154, CEP 13083-970, Campinas, SP, Brazil
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11
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Derivatization of Hydrophobic Amino Acids in Nonaqueous Media and Separation by Nonaqueous Capillary Electrophoresis with Laser-Induced Fluorescence Detection. Mikrochim Acta 2006. [DOI: 10.1007/s00604-006-0566-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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12
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Vandenabeele-Trambouze O, Claeys-Bruno M, Dobrijevic M, Rodier C, Borruat G, Commeyras A, Garrelly L. Comparison of methods for measurement of organic compounds at ultra-trace level: analytical criteria and application to analysis of amino acids in extraterrestrial samples. ASTROBIOLOGY 2005; 5:48-65. [PMID: 15711169 DOI: 10.1089/ast.2005.5.48] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The need for criteria to compare different analytical methods for measuring extraterrestrial organic matter at ultra-trace levels in relatively small and unique samples (e.g., fragments of meteorites, micrometeorites, planetary samples) is discussed. We emphasize the need to standardize the description of future analyses, and take the first step toward a proposed international laboratory network for performance testing.
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Affiliation(s)
- O Vandenabeele-Trambouze
- Organisation Moléculaire, Evolution et Matériaux Fluorés, UMR-CNRS 5073, Université Montpellier II, Montpellier, 2 Place E. Batallion 34195 Montpellier Cedex 5, France.
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13
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Continuous on-line derivatization and determination of amino acids by a microfluidic capillary electrophoresis system with a continuous sample introduction interface. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2003.09.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Chapter 14 Chromatography of amino acids and peptides. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/s0301-4770(04)80027-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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15
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Jaworska M, Szulińska Z, Wilk M. Development of a capillary electrophoretic method for the analysis of amino acids containing tablets. J Chromatogr A 2003; 993:165-72. [PMID: 12735449 DOI: 10.1016/s0021-9673(03)00394-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Ketosteril is an enteral medicinal product indicated for prevention and therapy in chronic renal insufficiency in connection with a low protein diet. Tablets of Ketosteril contain five essential amino acids like: Lys, His, Thr, Trp, Tyr and another five amino acids in the form of their hydroxy and keto analogues as calcium salts, that are: alpha-ketoleucine, alpha-ketoisoleucine, alpha-ketovaline, alpha-ketophenylalanine and alpha-hydroxymethionine. The composition of Ketosteril tablets is routinely tested with three LC methods. Capillary electrophoretic method seems to be a good alternative for amino acids and their analogues determination in multicomponent pharmaceuticals because of short analysis time and the possibility to assay all components during a single run without any pretreatment. Electrophoresis was performed in 50 microm I.D. fused-silica capillaries with 65 cm distance to the detector. Capillaries were installed in Waters Quanta 4000 electrophoretic equipment with a positive power supply and on-line UV detection at 214 nm. Separations were done in a buffer containing 40 mM Tris and 160 mM boric acid titrated with NaOH to pH 10. The method developed allows the separation of all investigated analytes with an efficiency of n = 230,000 and 20 min analysis time. The method was applied for determination of all components of Ketosteril in commercial tablets.
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Affiliation(s)
- Małgorzata Jaworska
- Department of Biological Preparations, Drug Institute, Chelmska 30134 Str., 00-725 Warsaw, Poland.
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16
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She Z, Sun Z, Wu L, Wu K, Sun S, Huang Z. Rapid method for the determination of amino acids in serum by capillary electrophoresis. J Chromatogr A 2002; 979:227-32. [PMID: 12498252 DOI: 10.1016/s0021-9673(02)01251-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A rapid method for the determination of amino acids in serum is presented. The derivatization of amino acids with 2,4-dinitrofluorobenzene was performed in 0.5 M sodium borate (pH 9.5). The complete separation of derivatives of 16 amino acids and an internal standard (D-norleucine) was achieved within 8 min by capillary zone electrophoresis. The running buffer consisted of 30 mM sodium tetraborate (pH 9.8)-isopropanol-30% Brij 35 (825:150:25, v/v). The capillary used had an internal diameter of 75 microm and an effective length of 300 mm. A voltage of 28 kV was applied. Temperature was maintained at 15 degrees C. Detection was 360 nm. The assay was linear from 10 to 700 microM. The minimal detection limit was 2.5-7.9 microM. The recovery of amino acids added to serum samples was 86.3-107.4%. Within-run precision was 2.8-10.3%, and between-run precision was 3.5-11.6%. The concentrations of amino acids in serum of 32 patients with chronic renal failure were measured. Among them, the levels of serine, isoleucine and valine were significantly lower than those of healthy volunteers (P<0.01), but the concentrations of cystine, tryptophan and phenylane were significantly higher than those of healthy volunteers (P<0.01). The result showed that the method could be used for determining amino acids in clinical practice and scientific research.
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Affiliation(s)
- Zuojun She
- Department of Clinical Chemistry, Anhui Provincial Center for Clinical Laboratory, 17 Lujiang Road, Hefei 230001, Anhui Province, China.
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Pumera M, Flegel M, Lepsa L, Jelínek I. Chiral analysis of biogenic DL-amino acids derivatized by urethane - protected alpha-amino acid N-carboxyanhydride using capillary zone electrophoresis and micellar electrokinetic chromatography. Electrophoresis 2002; 23:2449-56. [PMID: 12210202 DOI: 10.1002/1522-2683(200208)23:15<2449::aid-elps2449>3.0.co;2-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A new analytical method for enantioselective separation of DL-amino acids derivatized by N-fluorenylmethoxycarbonyl-L-alanyl N-carboxyanhydride (FMOC-L-Ala-NCA) using capillary electrophoresis was developed. Separation parameters, such as composition and pH of the background electrolyte, and concentration of gamma-cyclodextrin (in capillary zone electrophoresis) and sodium dodecyl sulfate (in micellar electrokinetic chromatography) were optimized. The separation method was validated and it suits well for purity analysis. Detection limit of the method was 0.2% of the minor enantiomer in the major one. The level of racemization in coupling during solid-phase peptide synthesis was studied using capillary electrophoresis with gamma-cyclodextrin as a chiral selector. The anchorage of the first (C-terminal) amino acid derivative to the solid supports bearing the hydroxylic groups is the key step of the synthesis affecting the extent of its racemization. FMOC-L-phenylalanine was chosen as the suitable model amino acid derivative making it possible to study the degree of racemization of N-fluorenylmethoxycarbonyl-L-alanine-L-phenylalanine synthesized on different polymer resins, using the different condensation agents.
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Affiliation(s)
- Martin Pumera
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003, USA.
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18
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Ma HM, Wang ZH, Su MH. New triazine spectroscopic reagent for the separation of DL-amino acids by micellar electrokinetic chromatography. J Chromatogr A 2002; 955:125-31. [PMID: 12061558 DOI: 10.1016/s0021-9673(02)00230-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
An approach to the chiral separation of racemic mixtures of amino acids by means of micellar electrokinetic chromatography after derivatization with a new triazine spectroscopic reagent, 3-(4,6-dichloro-1,3,5-triazinylamino)-7-dimethylamino-2-methylphenazine (DTDP), has been evaluated. It was found that the derivatives of the aliphatic amino acids such as serine, valine and arginine, could produce a strong UV absorption at 282 nm, whose apparent molar absorptivities are of 10(-4) M(-1) cm(-1), and thus the concentration of the amino acids down to 3 x 10(-7) M can still give a detectable signal (S/N = 3). Beta-Cyclodextrin (beta-CD) added to the buffer system was used as a chiral selector, and separation conditions were optimized. The presence of an organic modifier (2-propanol) was also a prerequisite for the chiral separation. The best results for the chiral separation of DTDP-amino acids were achieved in a mixed sodium dodecylsulfate-beta-CD-borate-2-propanol medium at pH 9.0. Compared to some of the commonly used derivatization methods, the present one offers a relatively stable derivative and strong UV absorption for the spectroscopically inert amino acids, thus enabling amino acids to be separated and detected by CE even with a simpler UV detector.
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Affiliation(s)
- Hui-Min Ma
- Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing.
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Abstract
The precapillary derivatization of 20 amino acids with naphthalene-2,3-dicarboxaldehyde (NDA) and CN(-) was investigated. All these derivatized amino acids could be oxidized on the carbon fiber microdisk bundle electrode except proline. Capillary zone electrophoresis with electrochemical detection was employed for the analysis of 19 amino acids. The optimum conditions of separation and detection were borate, pH 9.48, for the electrolyte, 18 kV for the separation voltage and 1.15 V versus a saturated calomel electrode for the detection potential. Limits of detection of concentration or mass for individual amino acids were between 1.7 x 10(-7) and 1.8 x 10(-6) mol/L or 84 and 893 amol (according to the signal-to-noise ratio of 3) for the injection voltage of 6 kV and injection time of 10 s. The relative standard deviations were between 0.80 and 2.3% for the migration times and 1.4 and 6.4% for the electrophoretic peak currents. From a mixture of 19 amino acids, 10 amino acids (Arg, Lys, Orn, Try, Ser, Ala, Gly, Cys, Glu, Asp) could be well separated. The other 9 amino acids appeared on three electrophoretic peaks. From the samples, in which the nine amino acids do not exist simultaneously, some of them could also be detected. The method was applied to the determination of amino acids in beer by the standard addition method. The recovery for the amino acids in beer was 91-109%.
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Affiliation(s)
- Qian Dong
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, China
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20
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Abstract
The aim of this study was to develop a general approach for characterizing the impurity profile of amino acids at level 0.1% by means of capillary electrophoresis (CE). Checking a variety of labeling reagents revealed 9-fluorenylmethyl chloroformate to be favorable, due to the high stability of its derivatives and the fact that the reagent peaks do not interfere with the peaks of the impurities. After optimization, the method was sufficiently sensitive to evaluate impurities at a 0.1% level by UV detection. The method was representatively validated for phenylalanine (Phe) with regard to selectivity, precision, linearity and accuracy using model mixtures of potential impurities. The CE analyzes method was applied to Phe samples of different manufacturers and the capabilities of the strategy was also demonstrated by samples of tryptophan and serine.
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Affiliation(s)
- N Novatchev
- Institute of Pharmacy and Food Chemistry, University of Würzburg, Am Hubland, 97074, Wurzburg, Germany
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21
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Wall W, Chan K, El Rassi Z. Electrically driven microseparation methods for pesticides and metabolites: VI. Surfactant-mediated electrokinetic capillary chromatography of aniline pesticidic metabolites derivatized with 9-fluoroenylmethyl chloroformate and their detection by laser-induced fluorescence. Electrophoresis 2001; 22:2320-6. [PMID: 11504068 DOI: 10.1002/1522-2683(20017)22:11<2320::aid-elps2320>3.0.co;2-o] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this report, we describe a surfactant-mediated electrokinetic capillary chromatography (SM-EKC) system for the separation of 9-fluoroenylmethyl chloroformate (FMOC)-derivatized anilines by capillary electrophoresis (CE). The SM-EKC system consisted of dioctyl sulfosuccinate (DOSS)/acetonitrile mixtures and was suited for the CE separation of the relatively hydrophobic FMOC-aniline analytes and other neutral compounds, e.g. alkylphenyl ketones. While the organic modifier acetonitrile (ACN) allowed the solubilization of the hydrophobic solutes and maintained the DOSS surfactant in its monomeric form by inhibiting micellization, the DOSS surfactant associated with the FMOC anilines to a varying degree thus leading to their differential migration and separation. Under these conditions, the FMOC-anilines were readily detected at the 10(-6) M level by UV at 214 nm and at the 10(-8) M level by laser-induced fluorescence (LIF) using a solid-state UV laser operating at 266 nm line as the excitation wavelength. The FMOC precolumn derivatization was also readily performed in lake water spiked with anilines at near the limit of detection (LOD) level. The lake water matrix showed no significant effects on the extent of derivatization at the LOD level as well as on the detection of the analytes due to the selectivity of the FMOC derivatization. The derivatization and detection of spiked lake water necessitated only the removal of microparticles by microfiltration prior to derivatization and detection.
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Affiliation(s)
- W Wall
- Department of Chemistry, Oklahoma State University, Stillwater 74078-3071, USA
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22
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Oguri S. Electromigration methods for amino acids, biogenic amines and aromatic amines. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2000; 747:1-19. [PMID: 11103896 DOI: 10.1016/s0378-4347(00)00092-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Methods of electromigration in laboratory apparatus of small-bore size have recently undergone development at a remarkably rapid pace, leading to a variety of new analytical techniques. One such technique is called "capillary electrophoresis" (CE), which is further classified on the basis of electromigration mode, viz., "capillary zone electrophoresis" (CZE), which, in turn, has several variations. This review aims to give a short overview of the various electromigration methods for amino compounds by using CE. Firstly, this review briefly summarizes the detection methods employed for detection of monoamines and polyamines by CE for both native and derivative forms. Next, current CE methods are described, and their applications to detection of amino acids, biogenic amines, aromatic amines, including heteroaromatic amines and their enantiomers, are introduced from representative papers. Finally, new methods for single-cell analysis and microchip CE techniques are focused on.
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Affiliation(s)
- S Oguri
- Department of Home Economics, Aichi-Gakusen University, Okazaki City, Japan
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Dugan ME, Thacker RD, Aalhus JL, Jermiah LE, Lien KA. Analysis of 4-hydroxyproline using 4-chloro-7-nitrobenzo-2-oxa-1,3-diazol derivatization and micellar electrokinetic chromatography combined with laser-induced fluorescence detection. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2000; 744:195-9. [PMID: 10985582 DOI: 10.1016/s0378-4347(00)00228-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Micellar electrokinetic chromatography (MEKC) with laser-induced fluorescence (LIF) detection was used for internal standard (pyrrolidinol) based quantification of 4-hydroxyproline (Hyp) in muscle hydrolysates. Hydrolysates were first derivatized with o-phthaldialdehyde to reduce primary amine interference and then 4-chloro-7-nitrobenzo-2-oxa-1,3-diazol (NBD) to enable selective detection of secondary amines. This method allows for rapid and sensitive detection of hydroxyproline in dilute hydrolysates using commercially available capillary electrophoresis equipment.
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Affiliation(s)
- M E Dugan
- Meat Research Section, Agriculture & Agri-Food Canada, Lacombe Research Centre.
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24
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Abstract
Since the introduction of the first commercial capillary electrophoresis (CE) instrument a decade ago, CE applications have become widespread. Today, CE is a versatile analytical technique which is successfully used for the separation of small ions, neutral molecules, and large biomolecules and for the study of physicochemical parameters. It is being utilized in widely different fields, such as analytical chemistry, forensic chemistry, clinical chemistry, organic chemistry, natural products, pharmaceutical industry, chiral separations, molecular biology, and others. It is not only used as a separation technique but to answer physicochemical questions. In this review, we will discuss different modes of CE such as capillary zone electrophoresis, micellar electrokinetic chromatography, capillary gel electrophoresis, capillary isoelectric focusing, and capillary electrochromatography, and will comment on the future direction of CE, including array capillary electrophoresis and array microchip separations.
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25
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Hu S, Li PC. Micellar electrokinetic capillary chromatographic separation and fluorescent detection of amino acids derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole. J Chromatogr A 2000; 876:183-91. [PMID: 10823513 DOI: 10.1016/s0021-9673(00)00163-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Another method has been developed for the separation of amino acids (1 min derivatization plus 22 min separation) by micellar electrokinetic capillary chromatography (MECC) with laser-induced fluorescence detection. Interestingly enough, such work has never been performed on essential amino acids derivatized by 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F). Fifteen L-amino acid standards were labelled with NBD-F at 60 degrees C for 1 min, and separated in a buffer system containing 20 mM borate, 25 mM sodium cholate, 10 mM Brij 35 and 2.5% methanol. Methanol was employed to expand the MECC migration time window; whereas Brij 35 was used to improve the fluorescence intensity of amino acid derivatives. This method also indicates that bile salt is effective for MECC separation of ionic analytes. Surprising though, improvements in resolution, sensitivity and speed for amino acids analysis are obtained in this work, which are not initially apparent in just employing another derivatizing reagent. Under optimal conditions, 15 amino acids were separated in a short 22 min analysis time, the shortest ever reported, and detection limits of nanomolar concentration and attomole mass were obtained. Furthermore, RSDs of migration time and peak height are better than 1% and 1.8%, respectively, again the smallest ever reported in the literature.
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Affiliation(s)
- S Hu
- Department of Biology and Chemistry, City University of Hong Kong, People's Republic of China
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26
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Abstract
Chiral separation of amino acids and peptides by capillary electrophoresis (CE) is reviewed regarding the separation principles of different approaches, advantages and limitations, chiral recognition mechanisms and applications. The direct approach details various chiral selectors with an emphasis on cyclodextrins and their derivatives, antibiotics and chiral surfactants as the chiral selectors. The indirect approach deals with various chiral reagents applied for diastereomer formation and types of separation media such as micelles and polymeric pseudo-stationary phases. Many derivatization reagents used for high sensitivity detection of amino acids and peptides are also discussed and their characteristics are summarized in tables. A large number of relevant examples is presented illustrating the current status of enantiomeric and diastereomeric separation of amino acids and peptides. Strategies to enhance the selectivity and optimize separation parameters by the application of experimental designs are described. The reversal of enantiomeric elution order and the effects of organic modifiers on the selectivity are illustrated in both direct and indirect methods. Some applications of chiral amino acid and peptide analysis, in particular, regarding the determination of trace enantiomeric impurities, are given. This review selects more than 200 articles published between 1988 and 1999.
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Affiliation(s)
- H Wan
- Department of Chemistry, Karlstad University, Sweden
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27
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Capillary electrophoresis of FITC labeled amino acids with laser-induced fluorescence detection. ACTA ACUST UNITED AC 1999. [DOI: 10.1007/bf02874333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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28
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Li J, Waldron KC. Estimation of the pH-independent binding constants of alanylphenylalanine and leucylphenylalanine stereoisomers with beta-cyclodextrin in the presence of urea. Electrophoresis 1999; 20:171-9. [PMID: 10065974 DOI: 10.1002/(sici)1522-2683(19990101)20:1<171::aid-elps171>3.0.co;2-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The separation of stereoisomers, particularly enantiomers, is important when their physiological activity differs. We have resolved the four stereoisomers each of alanylphenylalanine (Ala-Phe) and of leucylphenylalanine (Leu-Phe) by capillary electrophoresis using beta-cyclodextrin as a buffer additive and urea to enhance its solubility. A study of the influence of pH and beta-cyclodextrin concentration on the separations showed that weak inclusion complexes were formed between the dipeptides and chiral selector. It was found that pH could alter the migration order of enantiomers L-Ala-L-Phe and D-Ala-D-Phe, as well as L-Leu-L-Phe and D-Leu-D-Phe; however, there was no change in order for the other pairs of optical isomers. Electrophoretic mobility data were used to estimate the acid dissociation constants of the dipeptide isomers at pH < 7 with no chiral selector present. By varying the concentration of beta-cyclodextrin, the chiral selector, the binding constants of Ala-Phe and Leu-Phe optical isomers in their fully protonated and zwitterionic forms were estimated. For the four Ala-Phe stereoisomers, K = 42-66 M(-1) and 4-41 M(-1) for the cationic and zwitterionic forms, respectively. For the four Leu-Phe stereoisomers, K = 43-94 M(-1) and 1-28 M(-1) for the cationic and zwitterionic forms, respectively.
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Affiliation(s)
- J Li
- Institute for Biological Sciences, NRC, Ottawa, ON, Canada
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29
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Abstract
Amino acid composition analysis is a classical protein analysis method, which finds a wide application in medical and food science research and is indispensable for protein quantification. It is a complex technique, comprising two steps, hydrolysis of the substrate and chromatographic separation and detection of the residues. A properly performed hydrolysis is a prerequisite of a successful analysis. The most significant developments of the technology in the last decade consist in the (i) reduction of the hydrolysis time by the use of microwave radiation energy; (ii) improvement in the sensitivity of the residue detection, the quantification of the sensitive residues and separation of the enantiomeric forms of the amino acids; (iii) application of amino acid analysis in the large-scale protein identification by database search; and (iv) gradual replacement of the original ion exchange residue separation by reversed-phase high-performance liquid chromatography. Amino acid analysis is currently facing an enormous competition in the determination of the identity of proteins and amino acid homologs by the essentially faster mass spectrometry techniques. The amino acid analysis technology needs further simplification and automation of the hydrolysis, chromatography and detection steps to withstand the pressure exerted by the other technologies.
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Affiliation(s)
- M Fountoulakis
- F. Hoffman-La Roche Ltd., Pharma Division, Preclinical Central System--Gene Technology, Basel, Switzerland.
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30
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Couderc F, Caussé E, Bayle C. Drug analysis by capillary electrophoresis and laser-induced fluorescence. Electrophoresis 1998; 19:2777-90. [PMID: 9870374 DOI: 10.1002/elps.1150191605] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This review briefly presents the different laser-induced fluorescence detectors, outlines the different dyes used to derivatize molecules which are used with capillary electrophoresis/laser-induced fluorescence (CE-LIF), and provides an overview and current status of CE-LIF in drug analysis.
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Affiliation(s)
- F Couderc
- Université Paul Sabatier, Laboratoire de Biologie Moléculaire Eucaryotes, Toulouse, France.
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31
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Paquette DM, Sing R, Banks PR, Waldron KC. Capillary electrophoresis with laser-induced native fluorescence detection for profiling body fluids. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1998; 714:47-57. [PMID: 9746234 DOI: 10.1016/s0378-4347(98)00118-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Laser-induced native fluorescence detection with a KrF excimer laser (lambda=248 nm) was used to investigate the capillary electrophoretic (CE) profiles of human urine, saliva and serum without the need for sample derivatization. All separations were carried out in sodium phosphate and/or sodium tetraborate buffers at alkaline pH in a 50-microm I.D. capillary. Sodium dodecyl sulfate was added to the buffer for micellar electrokinetic chromatography (MEKC) analysis of human urine. Although inherently a pulsed source, the KrF excimer laser was operated at a high pulse repetition rate of 553, 1001 or 2009 Hz to simulate a continuous wave excitation source. Detection limits were found to vary with pulse rate, as expected, in proportion to average excitation power. The following detection limits (3sigma) were determined in free solution CE: tryptophan, 4 nM; conalbumin, 10 nM; alpha-lactalbumin, 30 nM. Detection limits for indole-based compounds and catecholamine urinary metabolites under MEKC separation conditions were in the range 7-170 nM.
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Affiliation(s)
- D M Paquette
- Department of Chemistry and Biochemistry, Concordia University, Montréal, Québec, Canada
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32
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Bardelmeijer HA, Lingeman H, de Ruiter C, Underberg WJ. Derivatization in capillary electrophoresis. J Chromatogr A 1998; 807:3-26. [PMID: 9646486 DOI: 10.1016/s0021-9673(98)00230-1] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In recent years capillary electrophoresis (CE) has been developed into a versatile separation technique, next to gas and liquid chromatography (LC), well suited for the determination of a wide variety of e.g., pharmaceutical, biomedical and environmental samples. The main advantages of CE over chromatographic separation techniques are its simplicity and efficiency. It is well recognized, however, that the sensitivity and selectivity of the detection are relatively weak points of CE. One way to overcome these limitations is the conversion (derivatization) of the analytes into product(s) with more favourable detection characteristics. Although, in principle, almost any detection mode can be combined with a derivatization procedure, in practice, fluorescence monitoring is favoured in most cases. This paper aims to give a short overview on the various reagents that can be used for pre-, post- and on-column derivatization in CE. First, a short introduction is given on CE as an analytical technique, followed by a discussion of the pros and cons of the various modes of derivatization, a comparison of derivatizations in CE with derivatizations in LC, the principles of fluorescence and prerequisites for a good fluorophore and the potential of using diode lasers in combination with a labelling procedure. With respect to the derivatization reagents the emphasis is on the labelling of amino, aldehyde, keto, carboxyl, hydroxyl and sulfhydryl groups.
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Affiliation(s)
- H A Bardelmeijer
- Utrecht University, Faculty of Pharmacy, Department of Pharmaceutical Analysis, Netherlands
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33
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Bardelmeijer HA, Waterval JC, Lingeman H, van't Hof R, Bult A, Underberg WJ. Pre-, on- and post-column derivatization in capillary electrophoresis. Electrophoresis 1997; 18:2214-27. [PMID: 9456036 DOI: 10.1002/elps.1150181212] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This survey gives a short overview of the various reagents and procedures that can be used for pre-, post- and on-column derivatization in capillary electrophoresis. First there is an introduction about capillary electrophoresis as an analytical technique; this is followed by a discussion of the pros and cons of the various modes of derivatization and a comparison with liquid chromatography. In the following paragraphs the reagents for a number of functional groups are discussed. The emphasis is on derivatization of the amino group. Most of the information on the reagents and derivatization procedures is listed in tables together with information on the detection mode, analytes, sensitivity and samples. In addition to the amino group, information is given on labeling of aldehyde, keto, carboxyl, hydroxyl and sulfhydryl groups.
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Affiliation(s)
- H A Bardelmeijer
- Department of Pharmaceutical Analysis, Utrecht University, The Netherlands
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34
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Abstract
The current status in the analysis of amino acids using capillary electrophoresis is addressed. This area of biological analysis has received increased attention with more than 200 articles being published in the last five years. This review discusses pre-, post-, and on-column derivatization techniques used to tag amino acids providing a detectable moiety. Several separation methodologies which provided resolution for large sets of amino acids are presented. An overview of advances in the enantiomeric resolution methodologies for amino acids is given. Both direct and indirect enantiomeric separation schemes are summarized. Recent advances in detection strategies for both derivatized and underivatized amino acids are presented. Applications utilizing amino acid analysis by capillary electrophoresis are described. This review covers articles published between 1991 and 1996.
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Affiliation(s)
- J T Smith
- Department of Physical Sciences, Southeastern Oklahoma State University, Durant 74701-0609, USA.
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35
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Abstract
Capillary electrophoresis (CE) and micellar electrokinetic chromatography were used for the separation of widely different compounds from natural materials including antibiotics, humic substances, flavonoids, isoflavonoids, illicit drugs, coumarins, alkaloids, steroids, Chinese herbal preparations, nicotine, caffeine, amphetamines, toxins such as aflatoxins B1, B2, G1, G2, mycotoxins, heptapeptide toxins and others, ephedrine compounds, mineral elements, and natural compounds in biological samples. A discussion of sample extraction and clean-up and the advantages of using CE is also presented.
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Affiliation(s)
- H J Issaq
- SAIC Frederick, NCI-Frederick Cancer Research and Development Center, MD 21702, USA.
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36
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Thorsén G, Engström A, Josefsson B. Enantiomeric determination of amino compounds with high sensitivity using the chiral reagents (+)- and (-)-1-(9-anthryl)-2-propyl chloroformate. J Chromatogr A 1997; 786:347-54. [PMID: 9408991 DOI: 10.1016/s0021-9673(97)00599-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
New chiral precolumn reagents, (+)- and (-)-1-(9-anthryl)-2-propyl chloroformate (APOC), are introduced for the chiral separation of amino acids and small peptides in capillary electrophoresis. Chiral separation of 17 amino acids and four small peptides as their diastereomeric 1-(9-anthryl)-2-propyl carbamate derivatives have been achieved by micellar electrokinetic chromatography. The detection limit for the derivatives is in the femtomole range with UV detection and in the attomole range with laser-induced fluorescence (LIF) detection. LIF detection was used to determine the enantiomeric excess of four APOC-derivatised peptides. The use of the new, anthracene-based reagents in conjunction with argon ion LIF makes enantiomeric determinations at ppm levels feasible. In this paper determinations below promille levels are performed without overloading the separation system.
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Affiliation(s)
- G Thorsén
- Department of Analytical Chemistry, Arrhenius Laboratories for Natural Sciences, Stockholm University, Stockholm
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37
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Abstract
This review surveys the use of micelles as separation media in chromatography and electrophoresis. Applications to pharmaceuticals whose molecular masses are relatively small are focused on in this review. In high-performance liquid chromatography (HPLC), chromatography using micelles and reversed-phase stationary phases such as octadecylsilylized silica gel (ODS) columns is known as micellar liquid chromatography (MLC). The main application of MLC to pharmaceutical analysis is the same as in ion-pair chromatography using alkylsulfonate or tetraalkylammonium. In most cases, selectivity is much improved compared with other short alkyl chain ion-pairing agents such as pentanesulfonate or octanesulfonate. Direct plasma/serum injection can be successful in MLC. Separation of small ions is also successful by using gel filtration columns and micellar solutions. In electrophoresis, especially capillary electrophoresis (CE), micelles are used as pseudo-stationary phases in capillary zone electrophoresis (CZE). This mode is called micellar electrokinetic chromatography (MEKC). Most of the drug analysis can be performed by using the MEKC mode because of its wide applicability. Enantiomer separation, separation of amino acids and closely related peptides, separation of very complex mixtures, determination of drugs in biological samples etc. as well as separation of electrically neutral drugs can be successfully achieved by MEKC. Microemulsion electrokinetic chromatography (MEEKC), in which surfactants are also used in forming the microemulsion, is successful for the separation of electrically neutral drugs as in MEKC. This review mainly describes the typical applications of MLC and MEKC for the analysis of pharmaceuticals.
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Affiliation(s)
- H Nishi
- Analytical Research Laboratory, Tanabe Seiyaku Co., Osaka, Japan
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38
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Muijselaar PG, Otsuka K, Terabe S. Micelles as pseudo-stationary phases in micellar electrokinetic chromatography. J Chromatogr A 1997; 780:41-61. [PMID: 9335128 DOI: 10.1016/s0021-9673(97)00632-8] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This review article describes some general comments on micellar electrokinetic chromatography (MEKC) from the viewpoint of pseudo-stationary phases and presents a compiled list of surfactants used for MEKC, prepared from published papers. We tried to give comments on some typical surfactants from the practical point of view.
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Affiliation(s)
- P G Muijselaar
- Faculty of Science, Himeji Institute of Technology, Hyogo, Japan
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39
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Guzman NA, Park SS, Schaufelberger D, Hernandez L, Paez X, Rada P, Tomlinson AJ, Naylor S. New approaches in clinical chemistry: on-line analyte concentration and microreaction capillary electrophoresis for the determination of drugs, metabolic intermediates, and biopolymers in biological fluids. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1997; 697:37-66. [PMID: 9342656 DOI: 10.1016/s0378-4347(97)00275-2] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The use of capillary electrophoresis (CE) for clinically relevant assays is attractive since it often presents many advantages over contemporary methods. The small-diameter tubing that holds the separation medium has led to the development of multicapillary instruments, and simultaneous sample analysis. Furthermore, CE is compatible with a wide range of detectors, including UV-Vis, fluorescence, laser-induced fluorescence, electrochemistry, mass spectrometry, radiometric, and more recently nuclear magnetic resonance, and laser-induced circular dichroism systems. Selection of an appropriate detector can yield highly specific analyte detection with good mass sensitivity. Another attractive feature of CE is the low consumption of sample and reagents. However, it is paradoxical that this advantage also leads to severe limitation, namely poor concentration sensitivity. Often high analyte concentrations are required in order to have injection of sufficient material for detection. In this regard, a series of devices that are broadly termed 'analyte concentrators' have been developed for analyte preconcentration on-line with the CE capillary. These devices have been used primarily for non-specific analyte preconcentration using packing material of the C18 type. Alternatively, the use of very specific antibody-containing cartridges and enzyme-immobilized microreactors have been demonstrated. In the current report, we review the likely impact of the technology of capillary electrophoresis and the role of the CE analyte concentrator-microreactor on the analysis of biomolecules, present on complex matrices, in a clinical laboratory. Specific examples of the direct analysis of physiologically-derived fluids and microdialysates are presented, and a personal view of the future of CE in the clinical environment is given.
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Affiliation(s)
- N A Guzman
- R. W. Johnson Pharmaceutical Research Institute, Raritan, NJ 08869, USA
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40
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Shihabi ZK, Friedberg MA. Analysis of small molecules for clinical diagnosis by capillary electrophoresis. Electrophoresis 1997; 18:1724-32. [PMID: 9372263 DOI: 10.1002/elps.1150181005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The application of capillary electrophoresis (CE) for the analysis of small molecules in clinical research is growing steadily. Initial studies have dealt with separations of standards or compounds in clean matrices. However, later studies dealt with analysis of those compounds in serum, urine or tissues. Great progress has been accomplished in three areas of clinical interest: organic acids, amino acids and drug analysis. The analysis of these compounds by capillary electrophoresis has several distinct advantages: high resolution, simplicity, versatility and especially low operating costs. In many cases, the sample can be injected directly without complex pretreatment. Most of the described methods have been validated for their precision, linearity and accuracy. In forensic toxicology, the CE has been used for drug identification and as a complementary analytical method.
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Affiliation(s)
- Z K Shihabi
- Department of Pathology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC 27157, USA.
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41
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Janini GM, Muschik GM, Issaq HJ. Micellar electrokinetic chromatography in zero-electroosmotic flow environment. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL APPLICATIONS 1996; 683:29-35. [PMID: 8876436 DOI: 10.1016/0378-4347(96)00130-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Micellar electrokinetic chromatography (MEKC) is conducted in polyacrylamide-coated capillaries under almost complete suppression of electroosmotic flow. The equations of migration and resolution for neutral solutes in this mode of MEKC operation are presented. The technique is termed reversed-flow MEKC (RF-MEKC) because, in contrast to MEKC in bare-silica capillaries (N-MEKC), solute migration order is reversed and solute migration time is inversely proportional to micelle concentration. This presents an advantage for the high-efficiency separation of extremely and moderately hydrophobic solutes in a short analysis time. Examples of the separation of polycyclic aromatic hydrocarbons, aflatoxins and dansylated-amino acids are presented using sodium dodecyl sulfate (SDS) surfactant. Polycyclic aromatic hydrocarbons are separated using a relatively low micelle concentration. The detection sensitivity for these compounds is enhanced in two ways. First, the peaks are sharp because of the short analysis time and the inertness of the column surface. Second, the fluorescence background and Joule's heating are minimal because of the low concentration of SDS and other additives needed to affect the separation. While N-MEKC is mainly conducted with basic buffers, RF-MEKC can be conducted in basic as well as acidic media as illustrated in the separation of 15 dansylated-amino acids at pH 4.2.
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Affiliation(s)
- G M Janini
- SAIC Frederick, NCI-Frederick Cancer Research and Development Center, MD 21702, USA
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42
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Abstract
Micellar electrokinetic chromatography (MEKC) has become a popular mode among several capillary electromigration techniques. Most drug analyses can be performed by using MEKC because of its wide applicability. Enantiomer separation, separation of closely related peptides and isotopic compounds, separation of very complex mixtures, determination of drugs in the biological samples, etc., can be successfully achieved by MEKC. This review surveys typical applications of MEKC analysis. Recent advances in MEKC, especially with pseudo-stationary phases, are described. Modes of electrokinetic chromatography including MEKC, a separation theory of MEKC and selectivity manipulation in MEKC are also briefly mentioned.
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Affiliation(s)
- H Nishi
- Analytical Research Laboratory, Tanabe Seiyaku Co., Ltd., Osaka, Japan
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43
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An argon-ion laser fluorometer optimal for concentration detection of 5-bromomethyl fluorescein derivatized carboxylic acids. Mikrochim Acta 1996. [DOI: 10.1007/bf01244962] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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44
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Amino acid and amino sugar determination by derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate followed by high-performance liquid chromatography and fluorescence detection. J Chromatogr A 1996. [DOI: 10.1016/0021-9673(95)00372-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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45
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Issaq HJ, Chan KC. Separation and detection of amino acids and their enantiomers by capillary electrophoresis: a review. Electrophoresis 1995; 16:467-80. [PMID: 7588513 DOI: 10.1002/elps.1150160178] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Since its introduction as an analytical technique capillary electrophoresis has been used for the separation of amino acids and their enantiomers; over 150 studies have been published to date. This review deals with their separation and detection. Amino acids have been resolved using both capillary zone electrophoresis and micellar electrokinetic chromatography. Pre-column derivatization schemes which are employed for the sensitive detection of amino acids are discussed. Criteria for the selection of the pre- or post-column derivatizing agent, chromophore or fluorophore, are presented. Detection systems, direct and indirect, that have been used are given with emphasis on fluorogenic reagents and laser induced fluorescence detection. Also, procedures for the separation of amino acid enantiomers are discussed and illustrated.
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Affiliation(s)
- H J Issaq
- Program Resources, Inc./DynCorp, NCI-Frederick Cancer Research and Development Center, MD 21702, USA
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46
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Chan KC, Muschik GM, Issaq HJ. Enantiomeric separation of amino acids using micellar electrokinetic chromatography after pre-column derivatization with the chiral reagent 1-(9-fluorenyl)-ethyl chloroformate. Electrophoresis 1995; 16:504-9. [PMID: 7588518 DOI: 10.1002/elps.1150160183] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Direct enantiomeric separations of some racemic amino acids derivatized with 9-fluorenylmethyl chloroformate were obtained using cyclodextrin-modified micellar electrokinetic chromatography (CD/MEKC) with a buffer made up of 5 mM sodium borate (pH 9.2), 150 mM sodium dodecyl sulfate (SDS) and 40 mM gamma-CD. Alternatively, enantiomeric separations were also achieved indirectly using MEKC after pre-column derivatization with (+)-1-(9-fluorenyl) ethyl chloroformate (FLEC). Using either a 10 mM sodium phosphate (pH 6.8) or a 5 mM sodium borate buffer (pH 9.2), each of which contained 25 mM SDS and 10-15% of acetonitrile, FLEC-derivatized serine, alanine, valine, methionine, leucine, phenylalanine, tryptophan, and their diastereomeric pairs were all separated: the L-isomers migrated faster than the corresponding D-isomers. However, when (-)-FLEC was used for derivatization, the D-isomers migrated faster than the corresponding L-isomers. Also, the diastereomers of aspartic acid, glutamic acid, and proline were resolved using a 10 mM sodium citrate buffer (pH 4.4). Using KrF (248 nm) laser-induced fluorescence, the detection limit of (+)-FLEC derivatized DL-amino acids was obtained at the nM level, which was about 100 x more sensitive than UV absorption at 200 nm. Analyte concentrations as low as 3 x 10(-8) M (DL-Val) could be derivatized with (+)-FLEC.
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Affiliation(s)
- K C Chan
- Program Resources, Inc/DynCorp, NCI-Frederick Cancer Research and Development Center, MD 21702, USA
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47
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Chan KC, Majadly F, McCloud TG, Muschik GM, Issaq HJ, Snader KM. Micellar electrokinetic chromatography of the anti-human immunodeficiency virus (HIV) agent michellamine B with absorption and laser-induced fluorescence detection. Electrophoresis 1994; 15:1310-5. [PMID: 7895724 DOI: 10.1002/elps.11501501199] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Micellar electrokinetic chromatography (MEKC) was applied to the separation of the anti-HIV agents, michellamines A and B, and two other structurally related monomers found in the extract of the Ancistrocladus plants. Using buffers containing either 10 mM sodium phosphate (pH 7.0), 50 mM sodium deoxycholate and 10-20% acetonitrile or 5 mM sodium phosphate (pH 7.0), 20 mM sodium dodecyl sulfate and 25% acetonitrile allowed baseline separations of the four components in the mixture in less than 10 min. The MEKC methods gave sharper peaks and better resolution compared to high-performance liquid chromatography. For MEKC separation of the plant extracts, UV absorption detection provided adequate sensitivity; however, higher sensitivity could be achieved with UV laser-induced fluorescence detection (LIF). Using the sodium dodecyl sulfate-containing buffer and LIF, the limit of detection for michellamine B was approximately 2 ng/mL. The sensitivity was degraded approximately 100-fold when using the deoxycholate buffer because of high background fluorescence. Preliminary results show that MEKC with LIF is feasible for the sensitive detection of michellamine B in serum.
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Affiliation(s)
- K C Chan
- Program Resources, Inc./DynCorp, National Cancer Institute, Frederick Cancer Research and Development Center, MD 21702
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Chan KC, Janini GM, Muschik GM, Issaq HJ. Micellar electrokinetic chromatography of hydroxyproline and other secondary amino acids in biological samples with laser-induced fluorescence detection. JOURNAL OF CHROMATOGRAPHY 1993; 622:269-73. [PMID: 8150876 DOI: 10.1016/0378-4347(93)80276-a] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Micellar electrokinetic chromatography (MEKC) with laser-induced fluorescence (LIF) was used for the rapid and sensitive detection of hydroxyproline in serum and hydrolyzed urine that were pre-column derivatized with 9-fluorenylmethyl chloroformate (FMOC). The application of the combined o-phthalaldehyde (OPA)/FMOC derivatization in MEKC for the selective detection of secondary amino acids in biological samples is investigated.
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Affiliation(s)
- K C Chan
- PRI/DynCorp, NCI Frederick Cancer Research and Development Center, MD 21702
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