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Thormann W, Mosher RA. Dynamic computer simulations of electrophoresis: 2010-2020. Electrophoresis 2021; 43:10-36. [PMID: 34287996 PMCID: PMC9292373 DOI: 10.1002/elps.202100191] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/12/2021] [Accepted: 07/15/2021] [Indexed: 02/05/2023]
Abstract
The transport of components in liquid media under the influence of an applied electric field can be described with the continuity equation. It represents a nonlinear conservation law that is based upon the balance laws of continuous transport processes and can be solved in time and space numerically. This procedure is referred to as dynamic computer simulation. Since its inception four decades ago, the state of dynamic computer simulation software and its use has progressed significantly. Dynamic models are the most versatile tools to explore the fundamentals of electrokinetic separations and provide insights into the behavior of buffer systems and sample components of all electrophoretic separation methods, including moving boundary electrophoresis, CZE, CGE, ITP, IEF, EKC, ACE, and CEC. This article is a continuation of previous reviews (Electrophoresis 2009, 30, S16–S26 and Electrophoresis 2010, 31, 726–754) and summarizes the progress and achievements made during the 2010 to 2020 time period in which some of the existing dynamic simulators were extended and new simulation packages were developed. This review presents the basics and extensions of the three most used one‐dimensional simulators, provides a survey of new one‐dimensional simulators, outlines an overview of multi‐dimensional models, and mentions models that were briefly reported in the literature. A comprehensive discussion of simulation applications and achievements of the 2010 to 2020 time period is also included.
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Affiliation(s)
- Wolfgang Thormann
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
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2
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Graf HG, Rudisch BM, Manegold J, Huhn C. Advancements in capacitance-to-digital converter-based C 4 D technology for detection in capillary electrophoresis using amplified excitation voltages and comparison to classical and open-source C 4 Ds. Electrophoresis 2021; 42:1306-1316. [PMID: 33710630 DOI: 10.1002/elps.202000394] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/28/2021] [Accepted: 03/08/2021] [Indexed: 11/05/2022]
Abstract
This work introduces new hardware configurations for a capacitively coupled contactless conductivity detector (C4 D) based on capacitance-to-digital conversion (CDC) technology for CE. The aim was to improve sensitivity, handling, price, and portability of CDC-based C4 D detectors (CDCD) to reach LODs similar to classic C4 Ds with more sophisticated electric circuits. To achieve this, a systematic study on the CDCDs was carried out including a direct comparison to already established C4 D setups. Instrumental setups differing in electrode lengths, measurement modes, and amplification of excitation voltages were investigated to achieve LODs for alkali metal ions of 4 to 12 μM, similar to LODs obtained by classic C4 D setups. Lowest LODs were achieved for a setup with two 10 mm electrodes at a distance of 0.2 mm and an excitation voltage of 24 V. The detection head was exceptionally lightweight with only 2.6 g and covered only 20 mm of the capillary on total. This allowed the use of multiple detectors along the separation path to enable spatial tracking of analytes during separation. The entirely battery-powered detector assembly weighs less than 200 g, and the data are transmitted wirelessly for possible portable applications. The freely accessible hardware and software were optimized for fully automated measurements with real time data plotting and allowed handling multidetector setups. The new developments were applied to quantify the potassium salt of glyphosate in its herbicide formulation.
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Affiliation(s)
- Hannes Georg Graf
- Institute of Physical and Theoretical Chemistry, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | | | - Johanna Manegold
- Institute of Physical and Theoretical Chemistry, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Carolin Huhn
- Institute of Physical and Theoretical Chemistry, Eberhard Karls Universität Tübingen, Tübingen, Germany
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3
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Maruška A, Drevinskas T, Stankevičius M, Bimbiraitė-Survilienė K, Kaškonienė V, Jonušauskas L, Gadonas R, Nilsson S, Kornyšova O. Single-chip based contactless conductivity detection system for multi-channel separations. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2021; 13:141-146. [PMID: 33320117 DOI: 10.1039/d0ay01882a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In this work, the design and characterization of a multi-cell capacitively coupled contactless conductivity detection system are described. The operation and simultaneous acquisition from 3 detector cells are demonstrated, however, the system is capable of supplying 8 detection cells and can be easily upgraded to maintain 64 capacitively coupled contactless conductivity detection cells. On performing flow-injection analysis, the system recorded as low as 0.01 mM of acetic acid, phosphoric acid, NaH2PO4, and Na2B4O7 solutions in water. The instrument was also capable of recording and distinguishing different mixtures of organic solvents: (a) methanol-acetonitrile, (b) hexane-acetone. The designed detection system is expected to be used coupled with multi-channel separation devices for monitoring simultaneous processes.
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Affiliation(s)
- Audrius Maruška
- Instrumental Analysis Open Access Centre, Faculty of Natural Sciences, Vytautas Magnus University, Vileikos 8, LT44404 Kaunas, Lithuania.
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4
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Le TB, Hauser PC, Pham TNM, Kieu TLP, Le TPQ, Hoang QA, Le DC, Nguyen TAH, Mai TD. Low-cost and versatile analytical tool with purpose-made capillary electrophoresis coupled to contactless conductivity detection: Application to antibiotics quality control in Vietnam. Electrophoresis 2020; 41:1980-1990. [PMID: 32856726 DOI: 10.1002/elps.202000163] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 08/24/2020] [Accepted: 08/25/2020] [Indexed: 12/12/2022]
Abstract
In this study, the development of our purpose-made capacitively coupled contactless conductivity detection (C4 D) for CE is reported. These systems have been employed as a simple, versatile, and cost-effective analytical tool. CE-C4 D devices, whose principle is based on the control of the ion movements under an electrical field, can be constructed even with a modest financial budget and limited infrastructure. A featured application was developed for quality control of antimicrobial drugs using CE-C4 D, with most recent work on determination of aminoglycoside and glycopeptide antibiotics being communicated. For aminoglycosides, the development of CE-C4 D methods was adapted to two categories. The first one includes drugs (liquid or powder form) for intravenous injection, containing either amikacin, streptomycin, kanamycin A, or kanamycin B. The second one covers drugs for eye drops (liquid or ointment form), containing either neomycin, tobramycin, or polymyxin. The CE-C4 D method development was also made for determination of some popular glycopeptide antibiotics in Vietnam, including vancomycin and teicoplanin. The best detection limit achieved using the developed CE-C4 D methods was 0.5 mg/L. Good agreement between results from CE-C4 D and the confirmation method (HPLC- Photometric Diode Array ) was achieved, with their result deviations less than 8% and 13% for aminoglycoside and glycopeptide antibiotics, respectively.
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Affiliation(s)
- Thai Binh Le
- Department of Analytical Chemistry, Faculty of Chemistry, University of Science, Vietnam National University, Hanoi, Hanoi, Vietnam
| | - Peter C Hauser
- Department of Chemistry, University of Basel, Basel, Switzerland
| | - Thi Ngoc Mai Pham
- Department of Analytical Chemistry, Faculty of Chemistry, University of Science, Vietnam National University, Hanoi, Hanoi, Vietnam
| | - Thi Lan Phuong Kieu
- Department of Analytical Chemistry, Faculty of Chemistry, University of Science, Vietnam National University, Hanoi, Hanoi, Vietnam
| | - Thi Phuong Quynh Le
- Institute of Natural Product Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Quoc Anh Hoang
- Department of Analytical Chemistry, Faculty of Chemistry, University of Science, Vietnam National University, Hanoi, Hanoi, Vietnam
| | - Dinh Chi Le
- Department of Analytical Chemistry and Toxicology, Hanoi University of Pharmacy, Hanoi, Vietnam
| | - Thi Anh Huong Nguyen
- Department of Analytical Chemistry, Faculty of Chemistry, University of Science, Vietnam National University, Hanoi, Hanoi, Vietnam
| | - Thanh Duc Mai
- CNRS, Institut Galien Paris-Saclay, Université Paris-Saclay, Châtenay-Malabry, France
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5
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de Castro Costa BM, Marra MC, da Costa Oliveira T, Munoz RAA, Batista AD, do Lago CL, Richter EM. Ultrafast capillary electrophoresis method for the simultaneous determination of ammonium and diphenhydramine in pharmaceutical samples. J Sep Sci 2018; 41:2969-2975. [PMID: 29785728 DOI: 10.1002/jssc.201800273] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 04/21/2018] [Accepted: 05/04/2018] [Indexed: 01/24/2023]
Abstract
Ammonium and diphenhydramine are active ingredients commonly found in the same pharmaceutical preparations. We report, for the first time, a sub-minute method for the simultaneous determination of ammonium and diphenhydramine. The method is based on capillary electrophoresis with capacitively coupled contactless conductivity detection. Both analytes can be quantified in a single run (∼80 injections/h) using 30 mmol/L 2-(N-morpholino)ethanesulfonic acid and 15 mmol/L lithium hydroxide (pH 6.0) as background electrolyte. The separation by capillary electrophoresis was achieved on a fused-silica capillary (50 cm total length, 10 cm effective length, and 50 μm inside diameter). The limits of detection were 0.04 and 0.02 mmol/L for ammonium and diphenhydramine, respectively. The proposed method also provided adequate recovery values for spiked samples (100-106 and 97-104% for ammonium and diphenhydramine, respectively). The results obtained with the new capillary electrophoresis method were compared with those of the high-performance liquid chromatography method for diphenhydramine and the Kjeldahl method for ammonium and no statistically significant differences were found (95% confidence level).
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Affiliation(s)
| | - Mariana Cardoso Marra
- Institute of Chemistry, Federal University of Uberlandia, Av. João Naves de Ávila, Uberlândia, Brazil
| | - Thiago da Costa Oliveira
- Institute of Chemistry, Federal University of Uberlandia, Av. João Naves de Ávila, Uberlândia, Brazil
| | | | - Alex Domingues Batista
- Institute of Chemistry, Federal University of Uberlandia, Av. João Naves de Ávila, Uberlândia, Brazil
| | - Claudimir Lucio do Lago
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, São Paulo, Brazil
| | - Eduardo Mathias Richter
- Institute of Chemistry, Federal University of Uberlandia, Av. João Naves de Ávila, Uberlândia, Brazil
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Paul P, Sänger-van de Griend C, Adams E, Van Schepdael A. Recent advances in the capillary electrophoresis analysis of antibiotics with capacitively coupled contactless conductivity detection. J Pharm Biomed Anal 2018; 158:405-415. [PMID: 29940496 DOI: 10.1016/j.jpba.2018.06.033] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 06/18/2018] [Accepted: 06/19/2018] [Indexed: 01/04/2023]
Abstract
This review describes briefly the high rate of counterfeiting of antimicrobial drugs with focus upon its immediate health consequences. The major part of this review encompasses accounts of the improvements achieved in the domain of miniaturization of capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D). The application of this principle into the development of portable devices as well as its application to counter the health-system-crippling phenomenon of counterfeit antibiotic formulations, are discussed in the context of developing countries.
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Affiliation(s)
- Prasanta Paul
- KU Leuven - University of Leuven, Pharmaceutical Analysis, Department of Pharmaceutical and Pharmacological Sciences, O&N2, PB 923, Herestraat 49, Leuven, 3000, Belgium
| | - Cari Sänger-van de Griend
- Department of Medicinal chemistry, Uppsala University, Husargatan 3, Uppsala, 751 23, Sweden; Kantisto BV, Callenburglaan 22, Baarn, 3742 MV, The Netherlands
| | - Erwin Adams
- KU Leuven - University of Leuven, Pharmaceutical Analysis, Department of Pharmaceutical and Pharmacological Sciences, O&N2, PB 923, Herestraat 49, Leuven, 3000, Belgium
| | - Ann Van Schepdael
- KU Leuven - University of Leuven, Pharmaceutical Analysis, Department of Pharmaceutical and Pharmacological Sciences, O&N2, PB 923, Herestraat 49, Leuven, 3000, Belgium.
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7
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20th anniversary of axial capacitively coupled contactless conductivity detection in capillary electrophoresis. Trends Analyt Chem 2018. [DOI: 10.1016/j.trac.2018.03.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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8
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Zhao S, Yin D, Du H, Tian X, Chen Y, Zhang W, Yu A, Zhang S. Determination of oxalate and citrate in urine by capillary electrophoresis using solid-phase extraction and capacitively coupled contactless conductivity based on an improved mini-cell. J Sep Sci 2018; 41:2623-2631. [DOI: 10.1002/jssc.201701432] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 03/08/2018] [Accepted: 03/09/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Shengnan Zhao
- College of Chemistry & Molecular Engineering; Zhengzhou University; Zhengzhou P. R. China
| | - Dan Yin
- College of Chemistry & Molecular Engineering; Zhengzhou University; Zhengzhou P. R. China
| | - Huifang Du
- College of Chemistry & Molecular Engineering; Zhengzhou University; Zhengzhou P. R. China
| | - Xiangyu Tian
- First Affiliated Hospital of Zhengzhou University; Zhengzhou P. R. China
| | - Yanlong Chen
- College of Chemistry & Molecular Engineering; Zhengzhou University; Zhengzhou P. R. China
| | - Wenfen Zhang
- College of Chemistry & Molecular Engineering; Zhengzhou University; Zhengzhou P. R. China
| | - Ajuan Yu
- College of Chemistry & Molecular Engineering; Zhengzhou University; Zhengzhou P. R. China
| | - Shusheng Zhang
- College of Chemistry & Molecular Engineering; Zhengzhou University; Zhengzhou P. R. China
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Le MD, Duong HA, Nguyen MH, Sáiz J, Pham HV, Mai TD. Screening determination of pharmaceutical pollutants in different water matrices using dual-channel capillary electrophoresis coupled with contactless conductivity detection. Talanta 2016; 160:512-520. [PMID: 27591645 DOI: 10.1016/j.talanta.2016.07.032] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Revised: 07/11/2016] [Accepted: 07/12/2016] [Indexed: 01/07/2023]
Abstract
In this study, the employment of purpose-made dual-channel compact capillary electrophoresis (CE) instrument with capacitively coupled contactless conductivity detection (C(4)D) as a simple and inexpensive solution for screening determination of various pharmaceutical pollutants frequently occurring in surface water and hospital wastewater in Hanoi, Vietnam is reported. Five negatively charged pharmaceutically active compounds, namely ibuprofen, diclofenac, bezafibrate, ketoprofen and mefenamic acid were determined using the first channel whereas three positively charged ones, namely diphenhydramine, metoprolol and atenolol were determined with the second channel of the CE-C(4)D instrument. Two different background electrolytes (BGEs) were used in these two CE channels independently. The best detection limits achieved were in the range of 0.2-0.8mg/L without sample pre-concentration. Enrichment factors up to 200 were obtainable with the inclusion of a solid phase extraction step. Good agreement between results obtained from CE-C(4)D and those with the standard confirmation method (HPLC-DAD) was achieved, with correlation coefficients higher than 0.98.
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Affiliation(s)
- Minh Duc Le
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Vietnam
| | - Hong Anh Duong
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Vietnam
| | - Manh Huy Nguyen
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Vietnam
| | - Jorge Sáiz
- Institute of General Organic Chemistry (IQOG), Spanish National Research Council (CSIC), Calle Juan de la Cierva, 3, Madrid, 28006 Spain
| | - Hung Viet Pham
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Vietnam.
| | - Thanh Duc Mai
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Vietnam.
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10
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Koenka IJ, Sáiz J, Rempel P, Hauser PC. Microfluidic Breadboard Approach to Capillary Electrophoresis. Anal Chem 2016; 88:3761-7. [PMID: 26926522 DOI: 10.1021/acs.analchem.5b04666] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A breadboard approach for electrophoretic separations with contactless conductivity detection is presented. This is based on miniature off-the-shelf components such as syringe pumps, valves, and pressure controllers which could be set up in a very compact overall arrangement. It has a high flexibility for different tasks at hand, and the common operations of hydrodynamic injection and capillary flushing are automated. For demonstration of the versatility of the proposition, several very diverse configurations and modes of electrophoresis were successfully implemented, namely, standard capillary zone electrophoresis, pressure assisted zone electrophoresis, the simultaneous separation of cations and anions by dual-capillary zone electrophoresis, the separation of cationic amino acids by isotachophoresis, as well as the separation of small carboxylic acids by gradient elution moving boundary electrophoresis. The system also allows fast separations, as demonstrated by the analysis of six inorganic cations within 35 s. The approach addresses respective limitations of either conventional capillary electrophoresis instruments as well as electrophoretic lab-on-chip devices, while maintaining a performance in terms of detection limits and reproducibility comparable to standard instrumentation.
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Affiliation(s)
- Israel Joel Koenka
- Department of Chemistry, University of Basel , Spitalstrasse 51, 4056 Basel, Switzerland
| | - Jorge Sáiz
- Department of Chemistry, University of Basel , Spitalstrasse 51, 4056 Basel, Switzerland.,Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, University of Alcalá , Ctra. Madrid-Barcelona Km 33.6, Alcalá de Henares, 28871, Madrid, Spain.,University Institute of Research in Police Sciences (IUICP), University of Alcalá , Ctra. Madrid-Barcelona Km 33.6, 28871 Alcalá de Henares, Madrid, Spain
| | - Paul Rempel
- Department of Chemistry, University of Basel , Spitalstrasse 51, 4056 Basel, Switzerland
| | - Peter C Hauser
- Department of Chemistry, University of Basel , Spitalstrasse 51, 4056 Basel, Switzerland
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11
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Beutner A, Cunha RR, Richter EM, Matysik FM. Combining C4
D and MS as a dual detection approach for capillary electrophoresis. Electrophoresis 2016; 37:931-5. [DOI: 10.1002/elps.201500512] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 12/23/2015] [Accepted: 12/23/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Andrea Beutner
- Institute for Analytical Chemistry, Chemo- and Biosensors; Regensburg Germany
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12
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Caslavska J, Koenka IJ, Hauser PC, Thormann W. Validation of CE modeling with a contactless conductivity array detector. Electrophoresis 2016; 37:699-710. [PMID: 26799858 DOI: 10.1002/elps.201500424] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 01/13/2016] [Accepted: 01/14/2016] [Indexed: 11/11/2022]
Abstract
Dynamic computer simulation data are compared for the first time with CE data obtained with a laboratory made system comprising an array of 8 contactless conductivity detectors (C(4) Ds). The experimental setup featured a 50 μm id linear polyacrylamide (LPA) coated fused-silica capillary of 70 cm length and a purpose built sequential injection analysis manifold for fluid handling of continuous or discontinuous buffer configurations and sample injection. The LPA coated capillary exhibits a low EOF and the manifold allows the placement of the first detector at about 2.7 cm from the sample inlet. Agreement of simulated electropherograms with experimental data was obtained for the migration and separation of cationic and anionic analyte and system zones in CZE configurations in which EOF and other column properties are constant. For configurations with discontinuous buffer systems, including ITP, experimental data obtained with the array detector revealed that the EOF is not constant. Comparison of simulation and experimental data of ITP systems provided the insight that the EOF can be estimated with an ionic strength dependent model similar to that previously used to describe EOF in fused-silica capillaries dynamically double coated with Polybrene and poly(vinylsulfonate). For the LPA coated capillaries, the electroosmotic mobility was determined to be 17-fold smaller compared to the case with the charged double coating. Simulation and array detection provide means for quickly investigating electrophoretic transport and separation properties. Without realistic input parameters, modeling alone is not providing data that match CE results.
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Affiliation(s)
- Jitka Caslavska
- Clinical Pharmacology Laboratory, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | | | - Peter C Hauser
- Department of Chemistry, University of Basel, Basel, Switzerland
| | - Wolfgang Thormann
- Clinical Pharmacology Laboratory, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
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Mai TD, Le MD, Sáiz J, Duong HA, Koenka IJ, Pham HV, Hauser PC. Triple-channel portable capillary electrophoresis instrument with individual background electrolytes for the concurrent separations of anionic and cationic species. Anal Chim Acta 2016; 911:121-128. [PMID: 26893094 DOI: 10.1016/j.aca.2016.01.029] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/12/2016] [Accepted: 01/16/2016] [Indexed: 01/15/2023]
Abstract
The portable capillary electrophoresis instrument is automated and features three independent channels with different background electrolytes to allow the concurrent optimized determination of three different categories of charged analytes. The fluidic system is based on a miniature manifold which is based on mechanically milled channels for injection of samples and buffers. The planar manifold pattern was designed to minimize the number of electronic valves required for each channel. The system utilizes pneumatic pressurization to transport solutions at the grounded as well as the high voltage side of the separation capillaries. The instrument has a compact design, with all components arranged in a briefcase with dimensions of 45 (w) × 35 (d) × 15 cm (h) and a weight of about 15 kg. It can operate continuously for 8 h in the battery-powered mode if only one electrophoresis channel is in use, or for about 2.5 h in the case of simultaneous employment of all three channels. The different operations, i.e. capillary flushing, rinsing of the interfaces at both capillary ends, sample injection and electrophoretic separation, are activated automatically with a control program featuring a graphical user interface. For demonstration, the system was employed successfully for the concurrent separation of different inorganic cations and anions, organic preservatives, additives and artificial sweeteners in various beverage and food matrices.
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Affiliation(s)
- Thanh Duc Mai
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Viet Nam
| | - Minh Duc Le
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Viet Nam
| | - Jorge Sáiz
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, University of Alcalá, Ctra. Madrid-Barcelona Km 33.6, Alcalá de Henares, Madrid, Spain
| | - Hong Anh Duong
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Viet Nam
| | - Israel Joel Koenka
- University of Basel, Department of Chemistry, Spitalstrasse 51, 4056 Basel, Switzerland
| | - Hung Viet Pham
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Viet Nam.
| | - Peter C Hauser
- University of Basel, Department of Chemistry, Spitalstrasse 51, 4056 Basel, Switzerland.
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14
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Affiliation(s)
- Rachel K Harstad
- University of Minnesota , Department of Chemistry, 207 Pleasant Street South East, Minneapolis, Minnesota 55455, United States
| | - Alexander C Johnson
- University of Minnesota , Department of Chemistry, 207 Pleasant Street South East, Minneapolis, Minnesota 55455, United States
| | - Megan M Weisenberger
- University of Minnesota , Department of Chemistry, 207 Pleasant Street South East, Minneapolis, Minnesota 55455, United States
| | - Michael T Bowser
- University of Minnesota , Department of Chemistry, 207 Pleasant Street South East, Minneapolis, Minnesota 55455, United States
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15
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Duong HA, Le MD, Nguyen KDM, Hauser PC, Pham HV, Mai TD. In-house-made capillary electrophoresis instruments coupled with contactless conductivity detection as a simple and inexpensive solution for water analysis: a case study in Vietnam. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2015; 17:1941-1951. [PMID: 26452107 DOI: 10.1039/c5em00362h] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A simple and inexpensive method for the determination of various ionic species in different water matrices is discussed in this study. The approach is based on the employment of in-house-made capillary electrophoresis (CE) instruments with capacitively coupled contactless conductivity detection (C(4)D), which can be realized even when only a modest financial budget and limited expertise are available. Advantageous features and considerations of these instruments are detailed following their pilot deployment in Vietnam. Different categories of ionic species, namely major inorganic cations (K(+), Na(+), Ca(2+), Mg(2+), and NH4(+)) and major inorganic anions (Cl(-), NO3(-), NO2(-), SO4(2-), and phosphate), in different water matrices in Vietnam were determined using these in-house fabricated instruments. Inorganic trivalent arsenic (As(iii)), which is the most abundant form of arsenic in reducing groundwater, was determined by CE-C(4)D. The effect of some interfering ions in groundwater on the analytical performance was investigated and is highlighted. The results from in-house-made CE-C(4)D-instruments were cross-checked with those obtained using the standard methods (AAS, AES, UV and IC), with correlation coefficients r(2) ≥ 0.9 and deviations from the referenced results less than 15%.
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Affiliation(s)
- Hong Anh Duong
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Vietnam.
| | - Minh Duc Le
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Vietnam.
| | - Kim Diem Mai Nguyen
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Vietnam.
| | - Peter C Hauser
- University of Basel, Department of Chemistry, Spitalstrasse 51, 4056 Basel, Switzerland
| | - Hung Viet Pham
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Vietnam.
| | - Thanh Duc Mai
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Vietnam.
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16
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Nguyen TAH, Pham TNM, Ta TT, Nguyen XT, Nguyen TL, Le THH, Koenka IJ, Sáiz J, Hauser PC, Mai TD. Screening determination of four amphetamine-type drugs in street-grade illegal tablets and urine samples by portable capillary electrophoresis with contactless conductivity detection. Sci Justice 2015; 55:481-6. [PMID: 26654084 DOI: 10.1016/j.scijus.2015.09.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 08/25/2015] [Accepted: 09/04/2015] [Indexed: 10/23/2022]
Abstract
A simple and inexpensive method for the identification of four substituted amphetamines, namely, 3,4-methylenedioxy methamphetamine (MDMA), methamphetamine (MA), 3,4-methylenedioxy amphetamine (MDA) and 3,4-methylenedioxy-N-ethylamphetamine (MDEA) was developed using an in-house constructed semi-automated portable capillary electrophoresis instrument (CE) with capacitively coupled contactless conductivity detection (C(4)D). Arginine 10mM adjusted to pH4.5 with acetic acid was found to be the optimal background electrolyte for the CE-C(4)D determination of these compounds. The best detection limits achieved with and without a sample preconcentration process were 10ppb and 500ppb, respectively. Substituted amphetamines were found in different seized illicit club drug tablets and urine samples collected from different suspected users. Good agreement between results from CE-C(4)D and those with the confirmation method (GC-MS) was achieved, with correlation coefficients for the two pairs of data of more than 0.99.
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Affiliation(s)
- Thi Anh Huong Nguyen
- Faculty of Chemistry, Department of Analytical Chemistry, Hanoi University of Science, Vietnam National University, 19 Le Thanh Tong, Hanoi, Viet Nam
| | - Thi Ngoc Mai Pham
- Faculty of Chemistry, Department of Analytical Chemistry, Hanoi University of Science, Vietnam National University, 19 Le Thanh Tong, Hanoi, Viet Nam
| | - Thi Thao Ta
- Faculty of Chemistry, Department of Analytical Chemistry, Hanoi University of Science, Vietnam National University, 19 Le Thanh Tong, Hanoi, Viet Nam
| | - Xuan Truong Nguyen
- Center of Drugs Expertise, Institute of Forensic Science, Ministry of Public Security, 99 Nguyen Tuan, Hanoi, Viet Nam
| | - Thi Lien Nguyen
- Faculty of Chemistry, Department of Analytical Chemistry, Hanoi University of Science, Vietnam National University, 19 Le Thanh Tong, Hanoi, Viet Nam
| | - Thi Hong Hao Le
- National Institute for Food Control (NIFC), 13 Phan Huy Chu, Hanoi, Viet Nam
| | - Israel Joel Koenka
- Department of Chemistry, University of Basel, Spitalstrasse 51, 4056 Basel, Switzerland
| | - Jorge Sáiz
- University Institute of Research in Police Sciences (IUICP), University of Alcalá, Ctra. Madrid, Barcelona Km 33.6, 28871 Alcalá de Henares (Madrid), Spain
| | - Peter C Hauser
- Department of Chemistry, University of Basel, Spitalstrasse 51, 4056 Basel, Switzerland
| | - Thanh Duc Mai
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Viet Nam.
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17
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Luo M, Ma H, Chen F. Effects of ion pairing on the capillary electrophoretic separation and ultraviolet-absorption detection of quaternary ammonium cations using meso-octamethylcalix[4]pyrrole as the background electrolyte additive. J Sep Sci 2015; 38:1225-31. [PMID: 25641935 DOI: 10.1002/jssc.201401208] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 01/01/2015] [Accepted: 01/02/2015] [Indexed: 12/18/2022]
Abstract
Five quaternary ammonium cations, including tetramethylammonium, tetraethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, and 1-butyl-3-methylimidazolium, have been separated by capillary electrophoresis. A direct ultraviolet method has been achieved when tetrabutylammonium fluoride was the background electrolyte and meso-octamethylcalix[4]pyrrole was the background electrolyte additive. The ultraviolet spectra of meso-octamethylcalix[4]pyrrole and cation mixtures showed that redshifts can be attributed to the size of cations, and the maximum absorption wavelength shifted from 218 to 230 nm when tetrabutylammonium cation was substituted with tetramethylammonium cation or tetraethylammonium cation. Conductivity measurements were performed to evaluate the ion-pairing effect of tetrabutylammonium fluoride in a mixture of acetonitrile/ethanol (80:20, v/v), and the ion-pairing formation constant, Kip, was calculated (Kip = 14.8 ± 0.3 L/mol) using the Fuoss extended model. Ion pairing also occurs between cations of the analytes and counterion, a fluoride complex of meso-octamethylcalix[4]pyrrole. The tetramethylammonium cations associate more strongly with this counterion than the tetraethylammonium cation that contributes to the change of selectivity in capillary electrophoresis separation. The effective mobilities of the cations with trimethyl groups, such as tetramethylammonium cation, benzyltrimethylammonium cation, and hexadecyltrimethylammonium cation, decreased faster than others with the increase of meso-octamethylcalix[4]pyrrole concentration, highlighting the fact that the ion-pairing effect played an important role in this method.
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Affiliation(s)
- Mina Luo
- College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, China
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18
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Sáiz J, Duc MT, Koenka IJ, Martín-Alberca C, Hauser PC, García-Ruiz C. Concurrent determination of anions and cations in consumer fireworks with a portable dual-capillary electrophoresis system. J Chromatogr A 2014; 1372C:245-252. [PMID: 25465022 DOI: 10.1016/j.chroma.2014.10.085] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 10/20/2014] [Accepted: 10/27/2014] [Indexed: 11/27/2022]
Abstract
A new automated portable dual-channel capillary electrophoresis instrument was built and applied to the concurrent determination of cations and anions. The system uses a single buffer and hydrodynamic injection of the sample is performed autonomously. A novel engraved flow-cell interface is used at the injection ends of the capillaries allowing the autonomous operation of the system. The engraved flow-cell replaces traditionally used split injectors in purpose made capillary electrophoresis systems and makes the system design easier. A new software package with graphical user interface was employed to control the system, making its operation simple and increasing its versatility. The electrophoretic method was optimized to allow the baseline separation of 12 cations and anions commonly found in fireworks. The system was proven to be useful for the analysis of consumer fireworks, saving time and expenses compared to separate analyses for anions and cations. This is the first time that cationic and anionic compositions of fireworks are investigated together. The analysis of samples revealed several inaccuracies between the declared compositions for the fireworks and the obtained results, which could be attributed to cross-contamination during their manufacture or to a transfer between other components of the pyrotechnic item. The presence of certain unexpected peaks, however, had no apparent reason and might represent an irregularity in the manufacture of some devices.
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Affiliation(s)
- Jorge Sáiz
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, University of Alcalá, Ctra. Madrid-Barcelona Km 33.6, 28871 Alcalá de Henares, Madrid, Spain; University Institute of Research in Police Sciences (IUICP), University of Alcalá, Ctra. Madrid-Barcelona Km 33.6, 28871 Alcalá de Henares, Madrid, Spain
| | - Mai Thanh Duc
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Viet Nam
| | - Israel Joel Koenka
- University of Basel, Department of Chemistry, Spitalstrasse 51, 4056 Basel, Switzerland
| | - Carlos Martín-Alberca
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, University of Alcalá, Ctra. Madrid-Barcelona Km 33.6, 28871 Alcalá de Henares, Madrid, Spain; University Institute of Research in Police Sciences (IUICP), University of Alcalá, Ctra. Madrid-Barcelona Km 33.6, 28871 Alcalá de Henares, Madrid, Spain
| | - Peter C Hauser
- University of Basel, Department of Chemistry, Spitalstrasse 51, 4056 Basel, Switzerland.
| | - Carmen García-Ruiz
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, University of Alcalá, Ctra. Madrid-Barcelona Km 33.6, 28871 Alcalá de Henares, Madrid, Spain; University Institute of Research in Police Sciences (IUICP), University of Alcalá, Ctra. Madrid-Barcelona Km 33.6, 28871 Alcalá de Henares, Madrid, Spain.
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19
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Sáiz J, Koenka IJ, Mai TD, Hauser PC, García-Ruiz C. Simultaneous separation of cations and anions in capillary electrophoresis. Trends Analyt Chem 2014. [DOI: 10.1016/j.trac.2014.07.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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20
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Kubáň P, Hauser PC. Contactless conductivity detection for analytical techniques-Developments from 2012 to 2014. Electrophoresis 2014; 36:195-211. [DOI: 10.1002/elps.201400336] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 08/05/2014] [Accepted: 08/05/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Pavel Kubáň
- Institute of Analytical Chemistry of the Academy of Sciences of the Czech Republic; Brno Czech Republic
| | - Peter C. Hauser
- Department of Chemistry; University of Basel; Basel Switzerland
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21
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Pham TTT, Mai TD, Nguyen TD, Sáiz J, Pham HV, Hauser PC. Automated dual capillary electrophoresis system with hydrodynamic injection for the concurrent determination of cations and anions. Anal Chim Acta 2014; 841:77-83. [DOI: 10.1016/j.aca.2014.05.046] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 05/15/2014] [Accepted: 05/25/2014] [Indexed: 01/25/2023]
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22
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Nguyen TAH, Pham TNM, Doan TT, Ta TT, Sáiz J, Nguyen TQH, Hauser PC, Mai TD. Simple semi-automated portable capillary electrophoresis instrument with contactless conductivity detection for the determination of β-agonists in pharmaceutical and pig-feed samples. J Chromatogr A 2014; 1360:305-11. [DOI: 10.1016/j.chroma.2014.07.074] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 07/18/2014] [Accepted: 07/24/2014] [Indexed: 11/29/2022]
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Capillary electrophoresis methods for microRNAs assays: a review. Anal Chim Acta 2014; 852:1-7. [PMID: 25441872 DOI: 10.1016/j.aca.2014.08.034] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Revised: 08/07/2014] [Accepted: 08/13/2014] [Indexed: 12/23/2022]
Abstract
MicroRNAs (miRNAs) are short noncoding RNAs that conduct important roles in many cellular processes such as development, proliferation, differentiation, and apoptosis. In particular, circulating miRNAs have been proposed as biomarkers for cancer, diabetes, cardiovascular disease, and other illnesses. Therefore, determination of miRNA expression levels in various biofluids is important for the investigation of biological processes in health and disease and for discovering their potential as new biomarkers and drug targets. Capillary electrophoresis (CE) is emerging as a useful analytical tool for analyzing miRNA because of its simple sample preparation steps and efficient resolution of a diverse size range of compounds. In particular, CE with laser-induced fluorescence detection is a promising and relatively rapidly developing tool with the potential to provide high sensitivity and specificity in the analysis of miRNAs. This paper covers a short overview of the recent developments and applications of CE systems in miRNA studies in biological and biomedical areas.
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