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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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2
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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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3
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Using chromatogram averaging to improve quantitation of minor impurities. J Chromatogr A 2016; 1465:205-10. [DOI: 10.1016/j.chroma.2016.08.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 08/15/2016] [Accepted: 08/20/2016] [Indexed: 11/20/2022]
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4
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Siegle AF, Trapp O. Improving the signal-to-noise ratio in gel permeation chromatography by Hadamard encoding. J Chromatogr A 2016; 1448:93-97. [DOI: 10.1016/j.chroma.2016.04.057] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 04/15/2016] [Accepted: 04/19/2016] [Indexed: 11/25/2022]
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5
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Siegle AF, Trapp O. Hyphenation of Hadamard Encoded Multiplexing Liquid Chromatography and Circular Dichroism Detection to Improve the Signal-to-Noise Ratio in Chiral Analysis. Anal Chem 2015; 87:11932-4. [DOI: 10.1021/acs.analchem.5b03705] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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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6
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Siegle AF, Trapp O. Implementation of Hadamard encoding for rapid multisample analysis in liquid chromatography. J Sep Sci 2015; 38:3839-3844. [DOI: 10.1002/jssc.201500849] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 08/31/2015] [Accepted: 09/01/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Alexander F. Siegle
- Organisch-Chemisches Institut; Ruprecht-Karls-Universität Heidelberg; Heidelberg Germany
| | - Oliver Trapp
- Organisch-Chemisches Institut; Ruprecht-Karls-Universität Heidelberg; Heidelberg Germany
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7
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Liu X, Tian M, Camara MA, Guo L, Yang L. Sequential capillary electrophoresis analysis using optically gated sample injection and UV/vis detection. Electrophoresis 2015; 36:2380-5. [DOI: 10.1002/elps.201500066] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 04/27/2015] [Accepted: 05/14/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Xiaoxia Liu
- Faculty of Chemistry; Northeast Normal University; ChangChun Jilin P. R. China
| | - Miaomiao Tian
- Faculty of Chemistry; Northeast Normal University; ChangChun Jilin P. R. China
| | | | - Liping Guo
- Faculty of Chemistry; Northeast Normal University; ChangChun Jilin P. R. China
| | - Li Yang
- Faculty of Chemistry; Northeast Normal University; ChangChun Jilin P. R. China
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8
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Hong Y, Niu W, Gao H, Xia L, Huang C, Shen C, Jiang H, Chu Y. Rapid identification of false peaks in the spectrum of Hadamard transform ion mobility spectrometry with inverse gating technique. RSC Adv 2015. [DOI: 10.1039/c5ra10245f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
With the introduction of inverse gating technique to Hadamard multiplexing ion mobility spectrometry, the false peaks in the spectrum of Hadamard transform could be rapidly identified.
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Affiliation(s)
- Yan Hong
- Laboratory of Medical Optical and Mass Spectrometry
- Center of Medical Physics and Technology
- Hefei Institutes of Physical Science
- Chinese Academy of Sciences
- Hefei 230031
| | - Wenqi Niu
- School of Science
- Anhui Agricultural University
- Hefei 230036
- China
| | - Hui Gao
- Laboratory of Medical Optical and Mass Spectrometry
- Center of Medical Physics and Technology
- Hefei Institutes of Physical Science
- Chinese Academy of Sciences
- Hefei 230031
| | - Lei Xia
- Laboratory of Medical Optical and Mass Spectrometry
- Center of Medical Physics and Technology
- Hefei Institutes of Physical Science
- Chinese Academy of Sciences
- Hefei 230031
| | - Chaoqun Huang
- Laboratory of Medical Optical and Mass Spectrometry
- Center of Medical Physics and Technology
- Hefei Institutes of Physical Science
- Chinese Academy of Sciences
- Hefei 230031
| | - Chengyin Shen
- Laboratory of Medical Optical and Mass Spectrometry
- Center of Medical Physics and Technology
- Hefei Institutes of Physical Science
- Chinese Academy of Sciences
- Hefei 230031
| | - Haihe Jiang
- Laboratory of Medical Optical and Mass Spectrometry
- Center of Medical Physics and Technology
- Hefei Institutes of Physical Science
- Chinese Academy of Sciences
- Hefei 230031
| | - Yannan Chu
- Laboratory of Medical Optical and Mass Spectrometry
- Center of Medical Physics and Technology
- Hefei Institutes of Physical Science
- Chinese Academy of Sciences
- Hefei 230031
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9
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Prost SA, Crowell KL, Baker ES, Ibrahim YM, Clowers BH, Monroe ME, Anderson GA, Smith RD, Payne SH. Detecting and removing data artifacts in Hadamard transform ion mobility-mass spectrometry measurements. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:2020-2027. [PMID: 24796262 PMCID: PMC4223016 DOI: 10.1007/s13361-014-0895-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/17/2014] [Accepted: 03/18/2014] [Indexed: 05/11/2023]
Abstract
Applying Hadamard transform multiplexing to ion mobility separations (IMS) can significantly improve the signal-to-noise ratio and throughput for IMS coupled mass spectrometry (MS) measurements by increasing the ion utilization efficiency. However, it has been determined that fluctuations in ion intensity as well as spatial shifts in the multiplexed data lower the signal-to-noise ratios and appear as noise in downstream processing of the data. To address this problem, we have developed a novel algorithm that discovers and eliminates data artifacts. The algorithm employs an analytical approach to identify and remove artifacts from the data, decreasing the likelihood of false identifications in subsequent data processing. Following application of the algorithm, IMS-MS measurement sensitivity is greatly increased and artifacts that previously limited the utility of applying the Hadamard transform to IMS are avoided. Figure ᅟ
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Affiliation(s)
- Spencer A Prost
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Kevin L Crowell
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Erin S Baker
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Yehia M Ibrahim
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Brian H Clowers
- Department of Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Matthew E Monroe
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Gordon A Anderson
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Richard D Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Samuel H Payne
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
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10
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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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11
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12
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Fan GT, Yang CL, Lin CH, Chen CC, Shih CH. Applications of Hadamard transform-gas chromatography/mass spectrometry to the detection of acetone in healthy human and diabetes mellitus patient breath. Talanta 2014; 120:386-90. [DOI: 10.1016/j.talanta.2013.12.025] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 12/10/2013] [Accepted: 12/11/2013] [Indexed: 11/27/2022]
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13
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Shi S, Zhao B, Yagnik G, Zhou F. An interface for sensitive analysis of monoamine neurotransmitters by ion-pair chromatography-electrospray ionization-mass spectrometry with continuous online elimination of ion-pair reagents. Anal Chem 2013; 85:6598-602. [PMID: 23767971 PMCID: PMC3780787 DOI: 10.1021/ac401396j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A challenge in coupling ion-pair chromatography (IPC) online with electrospray ionization-mass spectrometry (ESI-MS) is that the nonvolatile ion-pair reagent (e.g., alkyl sulfate for amines or tetrabutylammonium for carboxylic acids) in the mobile phase suppresses the ESI-MS signals in the gas phase and their accumulation can clog the MS sampling interface. Consequently, IPC-ESI-MS is conducted either with a volatile ion-pair reagent, which could compromise the analyte separation efficiency, or with a downstream ion-exchange column to rid the ion-pair reagents of the mobile phase. In the latter approach, the limited capacity of ion-exchange columns requires frequent off-line column regeneration, which affects the separation throughput and prohibits long separations from being performed. A dual-valve, dual-ion exchange column interface of IPC-ESI-MS is designed for undisrupted separations and simultaneous column regeneration. Owing to the efficacy in removing the ion-pair reagent, the detection of eluents of monoamine neurotransmitters by an ion trap MS results in the limits of detection of 0.03 μM for dopamine or DA and 0.01 μM for 5-hydroxytryptamine or 5-HT. These values are lower than those obtained with ion trap MS of similar sensitivity when combined with the use of specialized chromatographic columns or sample preconcentration. Excellent reproducibility was attained with repeatedly regenerated ion-exchange columns (RSD = 4-6%) for an extended period of time (RSD < 6% for 6 days). DA and 5-HT in rat straital extracts were analyzed, and our data demonstrate that interferences inherent in the tissues and the ion-pair reagent have been successfully eliminated. This simple interface should be readily amenable to the separation and MS analysis of other types of polar compounds in complex sample media.
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Affiliation(s)
- Shuyun Shi
- Department of Chemistry and Biochemistry, California State University, Los Angeles, Los Angeles, California 90032
- College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan, P. R. China 410083
| | - Binqing Zhao
- Department of Chemistry and Biochemistry, California State University, Los Angeles, Los Angeles, California 90032
| | - Gargey Yagnik
- Department of Chemistry and Biochemistry, California State University, Los Angeles, Los Angeles, California 90032
| | - Feimeng Zhou
- Department of Chemistry and Biochemistry, California State University, Los Angeles, Los Angeles, California 90032
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14
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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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15
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Cheng YK, Lin CH, Kuo S, Yang J, Hsiung SY, Wang JL. Applications of Hadamard transform-gas chromatography/mass spectrometry for the detection of hexamethyldisiloxane in a wafer cleanroom. J Chromatogr A 2012; 1220:143-6. [DOI: 10.1016/j.chroma.2011.12.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 11/21/2011] [Accepted: 12/01/2011] [Indexed: 11/25/2022]
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16
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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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17
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Cheng YK, Lin CH, Kaneta T, Imasaka T. Applications of Hadamard transform-gas chromatography/mass spectrometry to online detection of exhaled breath after drinking or smoking. J Chromatogr A 2010; 1217:5274-8. [DOI: 10.1016/j.chroma.2010.06.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 06/07/2010] [Accepted: 06/11/2010] [Indexed: 10/19/2022]
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18
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Cheng CC, Chang HW, Uchimura T, Imasaka T, Kaneta T, Lin CH. Application of Hadamard transform to gas chromatography/nonresonant multiphoton ionization/time-of-flight mass spectrometry. J Sep Sci 2010; 33:626-30. [DOI: 10.1002/jssc.200900662] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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19
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Fan Z, Lin CH, Chang HW, Kaneta T, Lin CH. Design and application of Hadamard-injectors coupled with gas and supercritical fluid sample collection systems in Hadamard transform-gas chromatography/mass spectrometry. J Chromatogr A 2010; 1217:755-60. [DOI: 10.1016/j.chroma.2009.12.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 11/18/2009] [Accepted: 12/02/2009] [Indexed: 10/20/2022]
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20
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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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21
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Kwasnik M, Caramore J, Fernández FM. Digitally-Multiplexed Nanoelectrospray Ionization Atmospheric Pressure Drift Tube Ion Mobility Spectrometry. Anal Chem 2009; 81:1587-94. [DOI: 10.1021/ac802383k] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Mark Kwasnik
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Joe Caramore
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Facundo M. Fernández
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332
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22
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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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Gas chromatographic high-throughput screening techniques in catalysis. J Chromatogr A 2007; 1184:160-90. [PMID: 18035362 DOI: 10.1016/j.chroma.2007.10.086] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Revised: 10/09/2007] [Accepted: 10/29/2007] [Indexed: 11/23/2022]
Abstract
Discovering highly efficient catalysts is of great scientific and economical interest. Advances in high-throughput assays in combination with sophisticated analytical techniques have increased the rapidity with which catalysts can be identified and optimized. Understanding how kinetics in the mechanism of catalysis is controlled by structural parameters is essential for a directed design of catalysts. To identify such rate-controlling elementary steps and to develop and refine models, comprehensive experimental kinetic data of a broad variety of substrates are necessary. In the present article concepts of high-throughput screening techniques in catalysis using gas chromatography are reviewed in a survey covering the period from 1998 to 2007. To cover also the origins of concepts and groundbreaking experiments in this research area milestones going back to 1950 are also reviewed. The first part of the review will focus on off-line gas chromatographic analysis, the second part on on-line gas chromatographic analysis covering sequential, parallelized and high-throughput multiplexing gas chromatography. The third part presents recent advances in the integration of chemical transformation and analysis in gas chromatography. The present review article describes the state-of-the-art, scope and limitations, and applications of these different high-throughput screening approaches.
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Braun KL, Hapuarachchi S, Fernandez FM, Aspinwall CA. High-sensitivity detection of biological amines using fast Hadamard transform CE coupled with photolytic optical gating. Electrophoresis 2007; 28:3115-21. [PMID: 17674422 DOI: 10.1002/elps.200700087] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Here, we report the first utilization of Hadamard transform CE (HTCE), a high-sensitivity, multiplexed CE technique, with photolytic optical gating sample injection of caged fluorescent labels for the detection of biologically important amines. Previous implementations of HTCE have relied upon photobleaching optical gating sample injection of fluorescent dyes. Photolysis of caged fluorescent labels reduces the fluorescence background, providing marked enhancements in sensitivity compared to photobleaching. Application of fast Hadamard transform CE (fHTCE) for fluorescein-based dyes yields a ten-fold higher sensitivity for photolytic injections compared to photobleaching injections, due primarily to the reduced fluorescent background provided by caged fluorescent dyes. Detection limits as low as 5 pM (ca. 18 molecules per injection event) were obtained with on-column LIF detection using fHTCE in less than 25 s, with the capacity for continuous, online separations. Detection limits for glutamate and aspartate below 150 pM (1-2 amol/injection event) were obtained using photolytic sample injection, with separation efficiencies exceeding 1 x 10(6) plates/m and total multiplexed separation times as low as 8 s. These results strongly support the feasibility of this approach for high-sensitivity dynamic chemical monitoring applications.
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Affiliation(s)
- Kevin L Braun
- Department of Chemistry, University of Arizona, Tucson, AZ 85721-0041, USA
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25
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26
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Affiliation(s)
- Oliver Trapp
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim/Ruhr, Germany.
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Seiman A, Kaljurand M, Ebber A. Influence of a stacking phenomenon on the results of Hadamard transform capillary electrophoresis. Anal Chim Acta 2007; 589:71-5. [PMID: 17397655 DOI: 10.1016/j.aca.2007.02.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Revised: 02/16/2007] [Accepted: 02/16/2007] [Indexed: 11/19/2022]
Abstract
Advantageous features (enhanced sensitivity and low baseline noise) of the multiplex measuring procedure, the Hadamard transform capillary electrophoresis (HT-CE), are experimentally demonstrated and critically discussed. To perform a perfect multiplex experiment in CE, sample species need to be dissolved in the background electrolyte medium and have very low concentration. The mismatch of electric conductivity resulting from a sample dissolved in water or in a separation buffer diluted with water will lead to sample stacking and corrupting the anticipated outcome. The multiplex measurements were carried out with benzyltriethylammonium bromide, resorcinol and 3,5-dihydroxybenzoic acid in the phosphate buffer, 511 sample/buffer injections were performed into the capillary according to the pseudorandom binary sequence. The averaged electropherogram of the single injection was calculated from the detection signal with the aid of the Fourier transform. The results illustrate the detrimental effect of sample matrix dilution with water and the effect of increased initial sample concentration on the multiplex measurement in CE. Multiplex advantage, in theory possible in the HT-CE, can be obtained at low concentration levels feasible with laser induced fluorescence and optically gated sampling. To achieve successful multiplex measurements with the UV detector, the single injection signal should be approximately at the baseline noise level.
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Affiliation(s)
- A Seiman
- Department of Chemistry, Faculty of Science, Tallinn University of Technology, Akadeemia tee 15, 126013 Tallinn, Estonia
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28
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KANETA T. Highly Sensitive Analysis Based on Laser-Induced Fluorescence Detection/Capillary Electrophoresis. BUNSEKI KAGAKU 2007. [DOI: 10.2116/bunsekikagaku.56.841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Takashi KANETA
- Department of Applied Chemistry, Graduate School of Engineering, Kyushu University
- Division of Translational Research, Center of Future Chemistry, Kyushu University
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