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Niezen LE, Bos TS, Schoenmakers PJ, Somsen GW, Pirok BWJ. Capacitively coupled contactless conductivity detection to account for system-induced gradient deformation in liquid chromatography. Anal Chim Acta 2023; 1271:341466. [PMID: 37328247 DOI: 10.1016/j.aca.2023.341466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 05/12/2023] [Accepted: 05/31/2023] [Indexed: 06/18/2023]
Abstract
The time required for method development in gradient-elution liquid chromatography (LC) may be reduced by using an empirical modelling approach to describe and predict analyte retention and peak width. However, prediction accuracy is impaired by system-induced gradient deformation, which can be especially prominent for steep gradients. As the deformation is unique to each LC instrument, it needs to be corrected for if retention modelling for optimization and method transfer is to become generally applicable. Such a correction requires knowledge of the actual gradient profile. The latter has been measured using capacitively coupled "contactless" conductivity detection (C4D), featuring a low detection volume (approximately 0.05 μL) and compatibility with very high pressures (80 MPa or more). Several different solvent gradients, from water to acetonitrile, water to methanol, and acetonitrile to tetrahydrofuran, could be measured directly without the addition of a tracer component to the mobile phase, exemplifying the universal nature of the approach. Gradient profiles were found to be unique for each solvent combination, flowrate, and gradient duration. The profiles could be described by convoluting the programmed gradient with a weighted sum of two distribution functions. Knowledge of the exact profiles was used to improve the inter-system transferability of retention models for toluene, anthracene, phenol, emodin, sudan-I and several polystyrene standards.
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Affiliation(s)
- Leon E Niezen
- Analytical-Chemistry Group, van 't Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), the Netherlands
| | - Tijmen S Bos
- Centre for Analytical Sciences Amsterdam (CASA), the Netherlands; Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands
| | - Peter J Schoenmakers
- Analytical-Chemistry Group, van 't Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), the Netherlands
| | - Govert W Somsen
- Centre for Analytical Sciences Amsterdam (CASA), the Netherlands; Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands
| | - Bob W J Pirok
- Analytical-Chemistry Group, van 't Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), the Netherlands.
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Tian S, Zhang W, Shi J, Guo Z, Li M. A Performance-enhanced Electroosmotic Pump with Track-etched Polycarbonate Membrane by Allylhydridopolycarbosilane Coating. ANAL SCI 2020; 36:953-957. [PMID: 32037348 DOI: 10.2116/analsci.19p452] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 01/27/2020] [Indexed: 08/09/2023]
Abstract
Nanochannel plastic membranes are excellent materials for electroosmotic pump (EOP) elements owing to their surface charge properties, flexibility and cost-effectiveness. However, the surface charge properties of plastics are inferior to those of silicate-based materials. This paper reports a performance-enhanced EOP equipped with a glassified track-etch polycarbonate membrane (PC), which has a nanochannel surface covered by allylhydridopolycarbosilane (AHPCS). The effects of applied voltage, pH and membrane pore size on the electroosmotic flow velocity, along with a comparative study of the EOP with coated and pure membranes were investigated. It was found that when low DC voltage (10 - 40 V) was applied to both ends of the pump, the magnitude of the electroosmotic flow was linearly proportional to the voltage when the pore size of the membrane was less than 600 nm. A higher flow rate was obtained with larger pore size membranes. Compared with the uncoated film, the coated one showed faster electroosmosis velocity, with higher stability under the same conditions. For pH 10.0 buffer solution, a flow rate of 89.13 μL/min was obtained in the modified membrane-based EOP with excellent repeatability and durability, while the flow rate was only 37.89 μL/min in the bare PC membrane under 20 V. In order to demonstrate the performance of the developed EOP, the EOP was used for microcomplexometric titration to determine actual tap water hardness. The measured results were highly consistent with the results of a conventional complexometric titration methed. The EOP with an AHPCS-coated plastic membrane expanded the application range to harsh condition solutions, such as high-concentration acids or bases.
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Affiliation(s)
- Shumei Tian
- Jiangsu Key Laboratory of Environmental Material and Environmental Engineering, College of Environmental Science and Engineering, Yangzhou University, Yangzhou, 225127, China
| | - Wenli Zhang
- Jiangsu Key Laboratory of Environmental Material and Environmental Engineering, College of Environmental Science and Engineering, Yangzhou University, Yangzhou, 225127, China
| | - Jinwei Shi
- Jiangsu Key Laboratory of Environmental Material and Environmental Engineering, College of Environmental Science and Engineering, Yangzhou University, Yangzhou, 225127, China
| | - Zixian Guo
- Jiangsu Key Laboratory of Environmental Material and Environmental Engineering, College of Environmental Science and Engineering, Yangzhou University, Yangzhou, 225127, China
| | - Ming Li
- Jiangsu Key Laboratory of Environmental Material and Environmental Engineering, College of Environmental Science and Engineering, Yangzhou University, Yangzhou, 225127, China.
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Li L, Wang X, Pu Q, Liu S. Advancement of electroosmotic pump in microflow analysis: A review. Anal Chim Acta 2019; 1060:1-16. [PMID: 30902323 DOI: 10.1016/j.aca.2019.02.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 02/07/2019] [Accepted: 02/09/2019] [Indexed: 01/21/2023]
Abstract
This review (with 152 references) covers the progress made in the development and application of electroosmotic pumps in a period from 2009 through 2018 in microflow analysis. Following a short introduction, the review first categorizes various electroosmotic pumps into five subclasses based on the materials used for pumping: i) open channel EOP, 2) packed-column EOP, iii) porous monolith EOP, iv) porous membrane EOP, and v) other types of EOP. Pumps in each subclass are discussed. A next section covers EOP applications, primarily the applications of EOPs in micro flow analysis and micro/nano liquid chromatography. Other scattered applications are also examined. Perspectives, trends and challenges are discussed in the final section.
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Affiliation(s)
- Lin Li
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu, 730000, PR China
| | - Xiayan Wang
- College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, 100124, PR China
| | - Qiaosheng Pu
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu, 730000, PR China.
| | - Shaorong Liu
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK, 73019, United States.
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Fornells E, Hilder EF, Shellie RA, Breadmore MC. On-line solvent exchange system: Automation from extraction to analysis. Anal Chim Acta 2019; 1047:231-237. [PMID: 30567655 DOI: 10.1016/j.aca.2018.09.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 09/05/2018] [Accepted: 09/17/2018] [Indexed: 11/30/2022]
Abstract
Removal of organic solvent from sample extracts is required before analysis by reversed phase HPLC to preserve chromatographic performance and allow for bigger injection volumes, boosting sensitivity. Herein, an automated on-line extraction evaporation procedure is integrated with HPLC analysis. The evaporation occurs inside a 200 μm microfluidic channel confined by a vapor permeable membrane. A feedback control algorithm regulates evaporation rate keeping the output flow rate constant. The evaporation process across this membrane was firstly characterized with water/solvent mixtures showing organic solvent removal capabilities. This system allowed continuous methanol, ethanol and acetonitrile removal from samples containing up to 80% organic solvent. An evaporative injection procedure was developed demonstrating the use of the device for fully integrated extract reconstitution coupled to HPLC analysis, applied to analysis of the antibiotic chloramphenicol in milk samples. Sample reconstitution and collection was performed in less than 10 min and can be executed simultaneously to HPLC analysis of the previous sample in a routine workflow, thus having minimal impact on the total sample analysis time when run in a sequence.
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Affiliation(s)
- Elisenda Fornells
- ARC Training Centre for Portable Analytical Separation Technologies (ASTech), Australia; ACROSS (Australian Centre for Research on Separation Science), University of Tasmania, Hobart, Tasmania, Australia
| | - Emily F Hilder
- ARC Training Centre for Portable Analytical Separation Technologies (ASTech), Australia; Future Industries Institute, University of South Australia, Adelaide, South Australia, Australia
| | - Robert A Shellie
- ARC Training Centre for Portable Analytical Separation Technologies (ASTech), Australia; Trajan Scientific and Medical, Ringwood, Victoria, Australia
| | - Michael C Breadmore
- ARC Training Centre for Portable Analytical Separation Technologies (ASTech), Australia; ACROSS (Australian Centre for Research on Separation Science), University of Tasmania, Hobart, Tasmania, Australia.
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Kubáň P, Hauser PC. Contactless conductivity detection for analytical techniques: Developments from 2016 to 2018. Electrophoresis 2018; 40:124-139. [PMID: 30010203 DOI: 10.1002/elps.201800248] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 07/10/2018] [Accepted: 07/10/2018] [Indexed: 01/05/2023]
Abstract
The publications concerning capacitively coupled contactless conductivity detection for the 2-year period from mid-2016 to mid-2018 are covered in this update to the earlier reviews of the series. Relatively few reports on fundamental investigations or new designs have appeared in the literature in this time interval, but the development of new applications with the detection method has continued strongly. Most often, contactless conductivity measurements have been employed for the detection of inorganic or small organic ions in conventional capillary electrophoresis, less often in microchip electrophoresis. A number of other uses, such as detection in chromatography or the gauging of bubbles in streams have also been reported.
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Affiliation(s)
- Pavel Kubáň
- Institute of Analytical Chemistry of the Czech Academy of Sciences, Brno, Czech Republic
| | - Peter C Hauser
- Department of Chemistry, University of Basel, Basel, Switzerland
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Lynch KB, Chen A, Yang Y, Lu JJ, Liu S. High-performance liquid chromatographic cartridge with gradient elution capability coupled with UV absorbance detector and mass spectrometer for peptide and protein analysis. J Sep Sci 2017; 40:2752-2758. [PMID: 28514057 DOI: 10.1002/jssc.201700185] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 05/05/2017] [Accepted: 05/08/2017] [Indexed: 02/05/2023]
Abstract
We discuss the construction and performance of a high-performance liquid chromatography cartridge that we developed that resulted from a culmination of previous research. We have recently developed an innovative approach to creating gradient elutions using dual electroosmotic pumps and a series of three valves. This method has been proved to be the most reproducible and robust in producing gradients compared to our previously tested methods. Using this approach, we have assembled a high-performance liquid chromatography cartridge powered and controlled via a computer. We have successfully coupled the cartridge with an ultraviolet absorbance detector and a mass spectrometer for separating complex protein/peptide samples. The cartridge is readily coupled with other detectors such as electrochemical detector and laser-induced fluorescence detector.
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Affiliation(s)
- Kyle B Lynch
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Apeng Chen
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Yu Yang
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Joann J Lu
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Shaorong Liu
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
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