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Kaneta T. Laser‐Induced Fluorometry for Capillary Electrophoresis. CHEM REC 2018; 19:452-461. [DOI: 10.1002/tcr.201800051] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 07/17/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Takashi Kaneta
- Department of ChemistryGraduate School of Natural Science and TechnologyOkayama University 3-1-1 Tsushimanaka Okayama 700-8530 Japan
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Pallmann S, Siegle AF, Šteflová J, Trapp O. Direct Hadamard Transform Capillary Zone Electrophoresis without Instrumental Modifications. Anal Chem 2018; 90:8445-8453. [PMID: 29886730 DOI: 10.1021/acs.analchem.8b01010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the first successful implementation of a multiplexing method on a standard capillary electrophoresis system with UV detection that is independent of additional hardware. This was achieved using the Hadamard transform approach and employing vial exchange and voltage suspensions for translation of pseudorandom binary sequence elements into sample and background electrolyte injections of a capillary zone electrophoresis separation. Sequences exceeding peak capacity of the capillary were subdivided into shorter subsequences measured successively and realigned afterward based on EOF marker or analyte peaks. This way, we realized and deconvoluted modulation sequences as long as 8-bit (255 injections) for two systems containing either AMP or a mixture of the nucleotides (A,C,G,U)MP resulting in electropherograms of considerably improved signal-to-noise ratio. We achieved factors of intensity enhancement of around 6.9 and 5.2, respectively (theoretical maximum 8.0). This contribution, further, presents experimental and simulation studies on the effects on zones during injection and separation when experiencing voltage suspensions. Besides analysis of EOF behavior and influence of diffusion dispersion, we also provide data on the significance of specific electrophoretic errors such as peak position shift, inconsistent sample injection, and peak broadening on the quality of the inverse Hadamard transform. Moreover, the application of our approach to the practical analysis of a milk sample is described. The results demonstrate the applicability of multiplexing on unmodified standard CE instrumentation and establish a new suitable methodology to enhance the low sensitivity of on-column UV detection in capillary electrophoresis.
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Affiliation(s)
- Sebastian Pallmann
- Ludwig-Maximilian University Munich , Faculty for Chemistry and Pharmacy , Butenandtstrasse 5-13 , 81377 Munich , Germany.,Max-Planck-Institute for Astronomy , Königstuhl 17 , 69117 Heidelberg , Germany
| | - Alexander F Siegle
- Ludwig-Maximilian University Munich , Faculty for Chemistry and Pharmacy , Butenandtstrasse 5-13 , 81377 Munich , Germany
| | - Jana Šteflová
- Ludwig-Maximilian University Munich , Faculty for Chemistry and Pharmacy , Butenandtstrasse 5-13 , 81377 Munich , Germany
| | - Oliver Trapp
- Ludwig-Maximilian University Munich , Faculty for Chemistry and Pharmacy , Butenandtstrasse 5-13 , 81377 Munich , Germany.,Max-Planck-Institute for Astronomy , Königstuhl 17 , 69117 Heidelberg , Germany
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Cifuentes Castro VH, López Valenzuela CL, Salazar Sánchez JC, Peña KP, López Pérez SJ, Ibarra JO, Villagrán AM. An update of the classical and novel methods used for measuring fast neurotransmitters during normal and brain altered function. Curr Neuropharmacol 2014; 12:490-508. [PMID: 25977677 PMCID: PMC4428024 DOI: 10.2174/1570159x13666141223223657] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 11/22/2014] [Accepted: 12/19/2014] [Indexed: 11/22/2022] Open
Abstract
To understand better the cerebral functions, several methods have been developed to study the brain activity, they could be related with morphological, electrophysiological, molecular and neurochemical techniques. Monitoring neurotransmitter concentration is a key role to know better how the brain works during normal or pathological conditions, as well as for studying the changes in neurotransmitter concentration with the use of several drugs that could affect or reestablish the normal brain activity. Immediate response of the brain to environmental conditions is related with the release of the fast acting neurotransmission by glutamate (Glu), γ-aminobutyric acid (GABA) and acetylcholine (ACh) through the opening of ligand-operated ion channels. Neurotransmitter release is mainly determined by the classical microdialysis technique, this is generally coupled to high performance liquid chromatography (HPLC). Detection of neurotransmitters can be done by fluorescence, optical density, electrochemistry or other detection systems more sophisticated. Although the microdialysis method is the golden technique to monitor the brain neurotransmitters, it has a poor temporal resolution. Recently, with the use of biosensor the drawback of temporal resolution has been improved considerably, however other inconveniences have merged, such as stability, reproducibility and the lack of reliable biosensors mainly for GABA. The aim of this review is to show the important advances in the different ways to measure neurotransmitter concentrations; both with the use of classic techniques as well as with the novel methods and alternant approaches to improve the temporal resolution.
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Affiliation(s)
| | | | | | | | | | | | - Alberto Morales Villagrán
- Department of Molecular and Cellular Biology, Camino Ramón Padilla Sánchez 2100, Nextipac, Zapopan,
Jalisco, México, Zip code: 45110, Mexico
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Siegle AF, Trapp O. Development of a Straightforward and Robust Technique to Implement Hadamard Encoded Multiplexing to High-Performance Liquid Chromatography. Anal Chem 2014; 86:10828-33. [DOI: 10.1021/ac502933f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alexander F. Siegle
- Organisch-Chemisches
Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer
Feld 270, 69120 Heidelberg, Germany
| | - Oliver Trapp
- Organisch-Chemisches
Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer
Feld 270, 69120 Heidelberg, Germany
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Gallagher ES, Comi TJ, Braun KL, Aspinwall CA. Online photolytic optical gating of caged fluorophores in capillary zone electrophoresis utilizing an ultraviolet light-emitting diode. Electrophoresis 2012; 33:2903-10. [PMID: 22911376 DOI: 10.1002/elps.201200279] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 06/23/2012] [Accepted: 06/25/2012] [Indexed: 11/11/2022]
Abstract
Photolytic optical gating (POG) facilitates rapid, on-line and highly sensitive analyses, though POG utilizes UV lasers for sample injection. We present a low-cost, more portable alternative, employing an ultraviolet light-emitting diode (UV-LED) array to inject caged fluorescent dyes via photolysis. Utilizing the UV-LED array, labeled amino acids were injected with nanomolar limits of detection (270 ± 30 nM and 250 ± 30 nM for arginine and citrulline, respectively). When normalized for the difference in light intensity, the UV-LED array provides comparable sensitivity to POG utilizing UV lasers. Additionally, the UV-LED array yielded sufficient beam quality and stability to facilitate coupling with a Hadamard transform, resulting in increased sensitivity. This work shows, for the first time, the use of an UV-LED for online POG with comparable sensitivity to conventional laser sources but at a lower cost.
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Affiliation(s)
- Elyssia S Gallagher
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
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Martin CS, Moriyama A, Zon LI. Hematopoietic stem cells, hematopoiesis and disease: lessons from the zebrafish model. Genome Med 2011; 3:83. [PMID: 22206610 PMCID: PMC3334548 DOI: 10.1186/gm299] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The zebrafish model is rapidly gaining prominence in the study of development, hematopoiesis, and disease. The zebrafish provides distinct advantages over other vertebrate models during early embryonic development by producing transparent, externally fertilized embryos. Embryonic zebrafish are easily visualized and manipulated through microinjection, chemical treatment, and mutagenesis. These procedures have contributed to large-scale chemical, suppressor, and genetic screens to identify hematopoietic gene mutations. Genomic conservation and local synteny between the human and zebrafish genomes make genome-scale and epigenetic analysis of these mutations (by microarray, chromatin immunoprecipitation sequencing, and RNA sequencing procedures) powerful methods for translational research and medical discovery. In addition, large-scale screening techniques have resulted in the identification of several small molecules capable of rescuing hematopoietic defects and inhibiting disease. Here, we discuss the contributions of the zebrafish model to the understanding of hematopoiesis, hematopoietic stem cell development, and disease-related discovery. We also highlight the recent discovery of small molecules with clinical promise, such as dimethyl prostaglandin E2, 3F8, and thiazole-carboxamide 10A.
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Affiliation(s)
- Corey S Martin
- Stem Cell Program and Division of Hematology/Oncology, Children's Hospital Boston, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02115, USA.
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Zhang ZX, Gao PF, Guo XF, Wang H, Zhang HS. 1,3,5,7-Tetramethyl-8-(N-hydroxysuccinimidyl butyric ester)difluoroboradiaza-s-indacene as a new fluorescent labeling reagent for HPLC determination of amino acid neurotransmitters in the cerebral cortex of mice. Anal Bioanal Chem 2011; 401:1905-14. [DOI: 10.1007/s00216-011-5253-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 07/12/2011] [Accepted: 07/13/2011] [Indexed: 11/30/2022]
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9
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Investigation of modulation parameters in multiplexing gas chromatography. J Chromatogr A 2010; 1217:6640-5. [DOI: 10.1016/j.chroma.2010.04.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Revised: 04/08/2010] [Accepted: 04/09/2010] [Indexed: 11/20/2022]
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Seiman A, Reijenga JC. Cross-correlation capillary electrophoresis in unmodified commercial equipment. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.proche.2009.12.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Poinsot VÃ, Gavard P, Feurer B, Couderc F. Recent advances in amino acid analysis by CE. Electrophoresis 2010; 31:105-21. [DOI: 10.1002/elps.200900399] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Perry M, Li Q, Kennedy RT. Review of recent advances in analytical techniques for the determination of neurotransmitters. Anal Chim Acta 2009; 653:1-22. [PMID: 19800472 PMCID: PMC2759352 DOI: 10.1016/j.aca.2009.08.038] [Citation(s) in RCA: 248] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 08/25/2009] [Accepted: 08/27/2009] [Indexed: 12/18/2022]
Abstract
Methods and advances for monitoring neurotransmitters in vivo or for tissue analysis of neurotransmitters over the last five years are reviewed. The review is organized primarily by neurotransmitter type. Transmitter and related compounds may be monitored by either in vivo sampling coupled to analytical methods or implanted sensors. Sampling is primarily performed using microdialysis, but low-flow push-pull perfusion may offer advantages of spatial resolution while minimizing the tissue disruption associated with higher flow rates. Analytical techniques coupled to these sampling methods include liquid chromatography, capillary electrophoresis, enzyme assays, sensors, and mass spectrometry. Methods for the detection of amino acid, monoamine, neuropeptide, acetylcholine, nucleoside, and soluble gas neurotransmitters have been developed and improved upon. Advances in the speed and sensitivity of these methods have enabled improvements in temporal resolution and increased the number of compounds detectable. Similar advances have enabled improved detection at tissue samples, with a substantial emphasis on single cell and other small samples. Sensors provide excellent temporal and spatial resolution for in vivo monitoring. Advances in application to catecholamines, indoleamines, and amino acids have been prominent. Improvements in stability, sensitivity, and selectivity of the sensors have been of paramount interest.
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Affiliation(s)
- Maura Perry
- University of Michigan, Department of Chemistry, 930 N. University, Ann Arbor, MI 48109-1055, USA
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Hudgens JW, Bergeron DE. A Hadamard transform electron ionization time-of-flight mass spectrometer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:014102. [PMID: 18248052 DOI: 10.1063/1.2838174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We describe the first Hadamard transform time-of-flight mass spectrometer (HT-TOFMS) that incorporates an electron (impact) ionization source. This implementation was realized in an existent TOF instrument using commercially available components and simple modifications to the ion source. In the present apparatus, a Hadamard mask is expressed by modulating the ion generation process within the ion source; thus, the present approach differs from previous designs that use external electrostatic devices to modulate a continuous ion stream. The present implementation may be operated in conventional TOF mode at 12.5 kHz and in HT-TOF mode at 20-40 MHz. In Hadamard mode the design can operate using any circulant simplex code, allowing the operator much flexibility for optimizing resolution and mass range and for eliminating nonstochastic fluctuations, e.g., encoding errors and signal hum. We demonstrate typical performance of the HT-TOFMS in standard and reflectron geometries using sequences of three constructions and of varied length, generating HT-TOF mass spectra of molecules that match conventional reference spectra. The auxiliary material includes an electrical schematic for the floating high-speed encoding amplifier, which is also of use in other high-speed electrostatic optics applications, and a list of 537 validated vectors comprising the first row of each circulant simplex sequence (S(n)=3-8219) derived using maximal shift register (n=2(m)-1), quadratic residue (n=4m-3), and twin prime constructions [n=p(p+2)].
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Affiliation(s)
- Jeffrey W Hudgens
- National Institute of Standards and Technology, Physical and Chemical Properties Division, 100 Bureau Drive, Stop 8380, Gaithersburg, Maryland 20899-8380, USA.
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