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van Mever M, Segers K, Drouin N, Guled F, Heyden YV, Van Eeckhaut A, Hankemeier T, Ramautar R. Direct profiling of endogenous metabolites in rat brain microdialysis samples by capillary electrophoresis-mass spectrometry with on-line preconcentration. Microchem J 2020. [DOI: 10.1016/j.microc.2020.104949] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Kubáň P, Dvořák M, Kubáň P. Capillary electrophoresis of small ions and molecules in less conventional human body fluid samples: A review. Anal Chim Acta 2019; 1075:1-26. [PMID: 31196414 DOI: 10.1016/j.aca.2019.05.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 05/02/2019] [Accepted: 05/03/2019] [Indexed: 01/05/2023]
Abstract
In recent years, advances in sensitive analytical techniques have encouraged the analysis of various compounds in biological fluids. While blood serum, blood plasma and urine still remain the golden standards in clinical, toxicological and forensic science, analyses of other body fluids, such as breast milk, exhaled breath condensate, sweat, saliva, amniotic fluid, cerebrospinal fluid, or capillary blood in form of dried blood spots are becoming more popular. This review article focuses on capillary electrophoresis and microchip electrophoresis of small ions and molecules (e.g. inorganic cations/anions, basic/acidic drugs, small acids/bases, amino acids, peptides and other low molecular weight analytes) in various less conventional human body fluids and hopes to stimulate further interest in the field.
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Affiliation(s)
- Petr Kubáň
- Institute of Analytical Chemistry of the Czech Academy of Sciences, Veveří 97, CZ-60200, Brno, Czech Republic
| | - Miloš Dvořák
- Institute of Analytical Chemistry of the Czech Academy of Sciences, Veveří 97, CZ-60200, Brno, Czech Republic
| | - Pavel Kubáň
- Institute of Analytical Chemistry of the Czech Academy of Sciences, Veveří 97, CZ-60200, Brno, Czech Republic.
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The future of immunocapture-capillary electrophoresis-high resolution mass spectrometry. Bioanalysis 2017; 9:1627-1631. [PMID: 29095042 DOI: 10.4155/bio-2017-4977] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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Plasma Membrane Na⁺-Coupled Citrate Transporter (SLC13A5) and Neonatal Epileptic Encephalopathy. Molecules 2017; 22:molecules22030378. [PMID: 28264506 PMCID: PMC6155422 DOI: 10.3390/molecules22030378] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 02/24/2017] [Accepted: 02/25/2017] [Indexed: 12/30/2022] Open
Abstract
SLC13A5 is a Na+-coupled transporter for citrate that is expressed in the plasma membrane of specific cell types in the liver, testis, and brain. It is an electrogenic transporter with a Na+:citrate3− stoichiometry of 4:1. In humans, the Michaelis constant for SLC13A5 to transport citrate is ~600 μM, which is physiologically relevant given that the normal concentration of citrate in plasma is in the range of 150–200 μM. Li+ stimulates the transport function of human SLC13A5 at concentrations that are in the therapeutic range in patients on lithium therapy. Human SLC13A5 differs from rodent Slc13a5 in two important aspects: the affinity of the human transporter for citrate is ~30-fold less than that of the rodent transporter, thus making human SLC13A5 a low-affinity/high-capacity transporter and the rodent Slc13a5 a high-affinity/low-capacity transporter. In the liver, SLC13A5 is expressed exclusively in the sinusoidal membrane of the hepatocytes, where it plays a role in the uptake of circulating citrate from the sinusoidal blood for metabolic use. In the testis, the transporter is expressed only in spermatozoa, which is also only in the mid piece where mitochondria are located; the likely function of the transporter in spermatozoa is to mediate the uptake of citrate present at high levels in the seminal fluid for subsequent metabolism in the sperm mitochondria to generate biological energy, thereby supporting sperm motility. In the brain, the transporter is expressed mostly in neurons. As astrocytes secrete citrate into extracellular medium, the potential function of SLC13A5 in neurons is to mediate the uptake of circulating citrate and astrocyte-released citrate for subsequent metabolism. Slc13a5-knockout mice have been generated; these mice do not have any overt phenotype but are resistant to experimentally induced metabolic syndrome. Recently however, loss-of-function mutations in human SLC13A5 have been found to cause severe epilepsy and encephalopathy early in life. Interestingly, there is no evidence of epilepsy or encephalopathy in Slc13a5-knockout mice, underlining the significant differences in clinical consequences of the loss of function of this transporter between humans and mice. The markedly different biochemical features of human SLC13A5 and mouse Slc13a5 likely contribute to these differences between humans and mice with regard to the metabolic consequences of the transporter deficiency. The exact molecular mechanisms by which the functional deficiency of the citrate transporter causes epilepsy and impairs neuronal development and function remain to be elucidated, but available literature implicate both dysfunction of GABA (γ-aminobutyrate) signaling and hyperfunction of NMDA (N-methyl-d-aspartate) receptor signaling. Plausible synaptic mechanisms linking loss-of-function mutations in SLC13A5 to epilepsy are discussed.
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Rodrigues KT, Cieslarová Z, Tavares MFM, Simionato AVC. Strategies Involving Mass Spectrometry Combined with Capillary Electrophoresis in Metabolomics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 965:99-141. [DOI: 10.1007/978-3-319-47656-8_5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Prior A, Sánchez-Hernández L, Sastre-Toraño J, Marina ML, de Jong GJ, Somsen GW. Enantioselective analysis of proteinogenic amino acids in cerebrospinal fluid by capillary electrophoresis-mass spectrometry. Electrophoresis 2016; 37:2410-9. [PMID: 27465690 DOI: 10.1002/elps.201600015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 06/06/2016] [Accepted: 06/15/2016] [Indexed: 11/06/2022]
Abstract
d-Amino acids (AAs) are increasingly being recognized as essential molecules in biological systems. Enantioselective analysis of proteinogenic AAs in biological samples was accomplished by CE-MS employing β-CD as chiral selector and ESI via sheath-liquid (SL) interfacing. Prior to analysis, AAs were fully derivatized with FMOC, improving AA-enantiomer separation and ESI efficiency. In order to optimize the separation and MS detection of FMOC-AAs, the effects of type and concentration of CD in the BGE, the composition of the SL, and MS-interfacing parameters were evaluated. Using a BGE of 10 mM β-CD in 50 mM ammonium bicarbonate (pH 8) containing 15% v/v isopropanol, a SL of isopropanol-water-1 M ammonium bicarbonate (50:50:1, v/v/v) at a flow rate of 3 μL/min, and a nebulizer gas pressure of 2 psi, 15 proteinogenic AAs could be detected with enantioresolutions up to 3.5 and detection limits down to 0.9 μM (equivalent to less than 3 pg AA injected). The selectivity of the method was demonstrated by the analysis of spiked cerebrospinal fluid, allowing specific detection of d-AAs. Repeatability and linearity obtained for cerebrospinal fluid were similar to standard solutions, with peak area and migration-time RSDs (n = 5) below 16.2 and 1.6%, respectively, and a linear response (R(2) ≥ 0.977) in the 3-90 μM range.
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Affiliation(s)
- Amir Prior
- Division of BioAnalytical Chemistry, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
| | - Laura Sánchez-Hernández
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Universidad de Alcalá, Alcalá de Henares (Madrid), Spain
| | - Javier Sastre-Toraño
- Division of Biomolecular Analysis, Utrecht University, CG Utrecht, The Netherlands
| | - Maria Luisa Marina
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Universidad de Alcalá, Alcalá de Henares (Madrid), Spain
| | - Gerhardus J de Jong
- Division of Biomolecular Analysis, Utrecht University, CG Utrecht, The Netherlands
| | - Govert W Somsen
- Division of BioAnalytical Chemistry, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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A fast and simple solid phase microextraction coupled with gas chromatography-triple quadrupole mass spectrometry method for the assay of urinary markers of glutaric acidemias. J Chromatogr A 2014; 1372C:253-259. [DOI: 10.1016/j.chroma.2014.10.069] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Revised: 09/29/2014] [Accepted: 10/24/2014] [Indexed: 11/17/2022]
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Kałużna-Czaplińska J, Żurawicz E, Struck W, Markuszewski M. Identification of organic acids as potential biomarkers in the urine of autistic children using gas chromatography/mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2014; 966:70-6. [DOI: 10.1016/j.jchromb.2014.01.041] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 01/21/2014] [Accepted: 01/23/2014] [Indexed: 11/15/2022]
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Kałużna-Czaplińska J, Żurawicz E, Jóźwik J. Chromatographic techniques coupled with mass spectrometry for the determination of organic acids in the study of autism. J Chromatogr B Analyt Technol Biomed Life Sci 2014; 964:128-35. [DOI: 10.1016/j.jchromb.2013.10.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 10/11/2013] [Accepted: 10/12/2013] [Indexed: 10/26/2022]
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Danč L, Bodor R, Troška P, Horčičiak M, Masár M. Determination of metabolic organic acids in cerebrospinal fluid by microchip electrophoresis. Electrophoresis 2014; 35:2146-54. [PMID: 24431209 DOI: 10.1002/elps.201300455] [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: 09/15/2013] [Revised: 11/11/2013] [Accepted: 12/24/2013] [Indexed: 11/10/2022]
Abstract
A new MCE method for the determination of oxalic, citric, glycolic, lactic, and 2- and 3-hydroxybutyric acids, indicators of some metabolic and neurological diseases, in cerebrospinal fluid (CSF) was developed. MCE separations were performed on a PMMA microchip with coupled channels at lower pH (5.5) to prevent proteins interference. A double charged counter-ion, BIS-TRIS propane, was very effective in resolving the studied organic acids. The limits of detection (S/N = 3) ranging from 0.1 to 1.6 μM were obtained with the aid of contact conductivity detector implemented directly on the microchip. RSDs for migration time and peak area of organic acids in artificial and CSF samples were <0.8 and <9.7%, respectively. Recoveries of organic acids in untreated CSF samples on the microchip varied from 91 to 104%. Elimination of chloride interference, a major anionic constituent of CSF, has been reached by two approaches: (i) the use of coupled channels microchip in a column switching mode when approximately 97-99% of chloride was removed electrophoretically in the first separation channel and (ii) the implementation of micro-SPE with silver-form resin prior to the MCE analysis, which selectively removed chloride from undeproteinized CSF samples.
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Affiliation(s)
- Ladislav Danč
- Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovak Republic
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Vaz FAS, da Silva PA, Passos LP, Heller M, Micke GA, Costa ACO, de Oliveira MAL. Optimisation of a capillary zone electrophoresis methodology for simultaneous analysis of organic aliphatic acids in extracts of Brachiaria brizantha. PHYTOCHEMICAL ANALYSIS : PCA 2012; 23:569-575. [PMID: 22407535 DOI: 10.1002/pca.2355] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 01/13/2012] [Accepted: 01/18/2012] [Indexed: 05/31/2023]
Abstract
INTRODUCTION Aluminum toxicity is commonly verified in acidic soils, and poses a severe limitation to plant growth and development. Therefore, Al complexation by the root system mucilage, Al complexation by organic compounds that are exuded by the roots and internal metabolic processes must be monitored by organic acids (OA), since they play a central role in these aluminum tolerance mechanisms. OBJECTIVE To optimise a capillary zone electrophoresis method able to perform simultaneous separation of acetic, citric, formic, lactic, malic, oxalic, pyruvic, succinic, tartaric and aspartic acid in plant extract solutions. METHODOLOGY Method optimisation was achieved by a chemometric approach through experimental designs. The optimal condition found was: 20 mmol/L phthalic acid buffer; 0.8 mmol/L cetyltrimethyl-ammonium bromide; pH 3.4 adjusted with tris(hydroxymethyl)aminomethane (around 16 mmol/L); -15 kV of voltage; 25 °C of cartridge temperature; indirect ultraviolet detection at 240 nm; and 25 mbar injection for 2 s, within an analysis time of 4 min. RESULTS As a repeatability test of the optimal condition, 30 replicates were carried out with the same working electrolyte, where the relative standard deviation of each peak ranged from 0.081 to 0.36% (for migration time) and from 2.4 to 4.6% (for peak area). CONCLUSION The methodology was successfully applied to simultaneously determine citric, malic and aspartic acid in roots and leaves extract solutions of Brachiaria brizantha, demonstrating its usefulness to study aluminum tolerance.
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Kühne S, Untucht C, Steinert M, Wätzig H. Fast investigations from biological matrices using CE – Test of a blood–brain barrier model. Electrophoresis 2012; 33:395-401. [DOI: 10.1002/elps.201100282] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Sascha Kühne
- Technische Universität Braunschweig, Institut für Pharmazeutische Chemie, Braunschweig, Germany
| | - Christopher Untucht
- Technische Universität Braunschweig, Institut für Mikrobiologie, Braunschweig, Germany
| | - Michael Steinert
- Technische Universität Braunschweig, Institut für Mikrobiologie, Braunschweig, Germany
| | - Hermann Wätzig
- Technische Universität Braunschweig, Institut für Pharmazeutische Chemie, Braunschweig, Germany
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Kauna-Czaplińska J. Current Applications of Gas Chromatography/Mass Spectrometry in the Study of Organic Acids in Urine. Crit Rev Anal Chem 2011. [DOI: 10.1080/10408347.2011.555242] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Kałużna-Czaplińska J. Noninvasive urinary organic acids test to assess biochemical and nutritional individuality in autistic children. Clin Biochem 2011; 44:686-91. [PMID: 21300048 DOI: 10.1016/j.clinbiochem.2011.01.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 12/29/2010] [Accepted: 01/30/2011] [Indexed: 10/18/2022]
Abstract
OBJECTIVES Quantitative organic acid testing can give information about potential problems, especially with energy production, neurotransmitter metabolism, intestinal dysbiosis and nutritional individuality which is very important in autistic children. The aim of this study was to find out potential differences between the levels of organic acids in the urine of autistic and non-autistic children. DESIGN AND METHODS The organic acids in the urine were determined by capillary gas chromatography/mass spectrometry (GC/MS). All overnight urine samples were collected from 35 autistic children and 36 neurologically normal children as healthy controls (4-10 years). RESULTS Significant differences were found between the autistic children and the control group in organic acids: 2-oxoglutaric, isocitric, citric, 4-hydroxybenzoic, 4-hydroxyphenylacetic, hippuric, adipic, suberic (all with p<0.05). CONCLUSION Organic acids test can be used to assess an individual need for nutrient and biochemical abnormalities, especially important for autistic children.
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Affiliation(s)
- Joanna Kałużna-Czaplińska
- Institute of General and Ecological Chemistry, Department of Chemistry, Technical University of Lodz, 116 Zeromskiego Str., 90–924 Lodz, Poland.
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Ramautar R, Toraño JS, Somsen GW, de Jong GJ. Evaluation of CE methods for global metabolic profiling of urine. Electrophoresis 2010; 31:2319-27. [DOI: 10.1002/elps.200900750] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Research Spotlight: Research at the Biomedical Analysis Group of the University Utrecht, The Netherlands. Bioanalysis 2010; 2:941-7. [DOI: 10.4155/bio.10.41] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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He J, Li J, Zhang Y, He Y, Sun W. Simultaneous Determination of Four Major Conjugated Cholic Acids in Dry Bile of Sus scrofa domestica Brisson by MEKC. Chromatographia 2010. [DOI: 10.1365/s10337-010-1536-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Erny GL, Rodrigues JEA, Gil AM, Barros AS, Esteves VI. Analysis of Non-Aromatic Organic Acids in Beer by CE and Direct Detection Mode with Diode Array Detection. Chromatographia 2009. [DOI: 10.1365/s10337-009-1377-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Huhn C, Ramautar R, Wuhrer M, Somsen GW. Relevance and use of capillary coatings in capillary electrophoresis–mass spectrometry. Anal Bioanal Chem 2009; 396:297-314. [DOI: 10.1007/s00216-009-3193-y] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 09/22/2009] [Accepted: 09/24/2009] [Indexed: 11/24/2022]
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Abstract
Sample stacking techniques remain an important tool for enhancement of the selectivity and sensitivity of analyses in contemporary CZE. This contribution reviews new knowledge on this topic published since 2006. It is organized according to the operational principles used, which include concentration adjustment, application of a pH step, MEKC and sweeping, and transient ITP. Techniques combining several of these principles and comparative studies are also included.
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Affiliation(s)
- Zdena Malá
- Institute of Analytical Chemistry of the ASCR, Brno, Czech Republic
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Ramautar R, Mayboroda OA, Derks RJE, van Nieuwkoop C, van Dissel JT, Somsen GW, Deelder AM, de Jong GJ. Capillary electrophoresis-time of flight-mass spectrometry using noncovalently bilayer-coated capillaries for the analysis of amino acids in human urine. Electrophoresis 2008; 29:2714-22. [PMID: 18494035 DOI: 10.1002/elps.200700929] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A capillary electrophoresis-time of flight-mass spectrometry (CE-TOF-MS) method for the analysis of amino acids in human urine was developed. Capillaries noncovalently coated with a bilayer of Polybrene (PB) and poly(vinyl sulfonate) (PVS) provided a considerable EOF at low pH, thus facilitating the fast separation of amino acids using a BGE of 1 M formic acid (pH 1.8). The PB-PVS coating proved to be very consistent yielding stable CE-MS patterns of amino acids in urine with favorable migration time repeatability (RSDs <2%). The relatively low sample loading capacity of CE was circumvented by an in-capillary preconcentration step based on pH-mediated stacking allowing 100-nL sample injection (i.e. ca. 4% of capillary volume). As a result, LODs for amino acids were down to 20 nM while achieving satisfactory separation efficiencies. Preliminary validation of the method with urine samples showed good linear responses for the amino acids (R(2) >0.99), and RSDs for peak areas were <10%. Special attention was paid to the influence of matrix effects on the quantification of amino acids. The magnitude of ion suppression by the matrix was similar for different urine samples. The CE-TOF-MS method was used for the analysis of urine samples of patients with urinary tract infection (UTI). Concentrations of a subset of amino acids were determined and compared with concentrations in urine of healthy controls. Furthermore, partial least squares-discriminant analysis (PLS-DA) of the CE-TOF-MS dataset in the 50-450 m/z region showed a distinctive grouping of the UTI samples and the control samples. Examination of score and loadings plot revealed a number of compounds, including phenylalanine, to be responsible for grouping of the samples. Thus, the CE-TOF-MS method shows good potential for the screening of body fluids based on the analysis of endogenous low-molecular weight metabolites such as amino acids and related compounds.
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Affiliation(s)
- Rawi Ramautar
- Department of Biomedical Analysis, Utrecht University, Utrecht, The Netherlands.
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Metabolic analysis of body fluids by capillary electrophoresis using noncovalently coated capillaries. J Chromatogr B Analyt Technol Biomed Life Sci 2008; 871:370-4. [DOI: 10.1016/j.jchromb.2008.06.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 05/21/2008] [Accepted: 06/02/2008] [Indexed: 11/19/2022]
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Capillary electrophoresis analysis of biofluids with a focus on less commonly analyzed matrices. J Chromatogr B Analyt Technol Biomed Life Sci 2008; 866:154-66. [DOI: 10.1016/j.jchromb.2008.01.058] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 01/23/2008] [Accepted: 01/24/2008] [Indexed: 12/19/2022]
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Simpson SL, Quirino JP, Terabe S. On-line sample preconcentration in capillary electrophoresis. J Chromatogr A 2008; 1184:504-41. [DOI: 10.1016/j.chroma.2007.11.001] [Citation(s) in RCA: 269] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Revised: 10/30/2007] [Accepted: 11/01/2007] [Indexed: 02/06/2023]
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