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Li L, Ren DD, Zhang PY, Song YP, Li TX, Gao MH, Xu JN, Zhou L, Zeng ZC, Pu Q. Pushing the Limits of Capacitively Coupled Contactless Conductivity Detection for Capillary Electrophoresis. Anal Chem 2024; 96:10356-10364. [PMID: 38863415 DOI: 10.1021/acs.analchem.4c01367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
Capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) has proven to be an efficient technique for the separation and detection of charged inorganic, organic, and biochemical analytes. It offers several advantages, including cost-effectiveness, nanoliter injection volume, short analysis time, good separation efficiency, suitability for miniaturization, and portability. However, the routine determination of common inorganic cations (NH4+, K+, Na+, Ca2+, Mg2+, and Li+) and inorganic anions (F-, Cl-, Br-, NO2-, NO3-, PO43-, and SO42-) in water quality monitoring typically exhibits limits of detection of about 0.3-1 μM without preconcentration. This sensitivity often proves insufficient for the applications of CE-C4D in trace analysis situations. Here, we explore methods to push the detection limits of CE-C4D through a comprehensive consideration of signal and noise sources. In particular, we (i) studied the model of C4D and its guiding roles in C4D and CE-C4D, (ii) optimized the bandwidth and noise performance of the current-to-voltage (I-V) converter, and (iii) reduced the noise level due to the strong background signal of the background electrolyte by adaptive differential detection. We characterized the system with Li+; the 3-fold signal-to-noise (S/N) detection limit for Li+ was determined at 20 nM, with a linear range spanning from 60 nM to 1.6 mM. Moreover, the optimized CE-C4D method was applied to the analysis of common mixed inorganic cations (K+, Na+, Ca2+, Mg2+, and Li+), anions (F-, Cl-, Br-, NO2-, NO3-, PO43-, and SO42-), toxic halides (BrO3-) and heavy metal ions (Pb2+, Cd2+, Cr3+, Co2+, Ni2+, Zn2+, and Cu2+) at trace concentrations of 200 nM. All electropherograms showed good S/N ratios, thus proving its applicability and accuracy. Our results have shown that the developed CE-C4D method is feasible for trace ion analysis in water quality control.
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Affiliation(s)
- Lin Li
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Dou-Dou Ren
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Peng-Yu Zhang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Yun-Peng Song
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Tang-Xiu Li
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Ming-Hui Gao
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Jia-Nan Xu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Lei Zhou
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Zhi-Cong Zeng
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Qiaosheng Pu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
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2
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Warren CG, Dasgupta PK. Liquid phase detection in the miniature scale. Microfluidic and capillary scale measurement and separation systems. A tutorial review. Anal Chim Acta 2024; 1305:342507. [PMID: 38677834 DOI: 10.1016/j.aca.2024.342507] [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: 01/08/2024] [Revised: 03/18/2024] [Accepted: 03/19/2024] [Indexed: 04/29/2024]
Abstract
Microfluidic and capillary devices are increasingly being used in analytical applications while their overall size keeps decreasing. Detection sensitivity for these microdevices gains more importance as device sizes and consequently, sample volumes, decrease. This paper reviews optical, electrochemical, electrical, and mass spectrometric detection methods that are applicable to capillary scale and microfluidic devices, with brief introduction to the principles in each case. Much of this is considered in the context of separations. We do consider theoretical aspects of separations by open tubular liquid chromatography, arguably the most potentially fertile area of separations that has been left fallow largely because of lack of scale-appropriate detection methods. We also examine the theoretical basis of zone electrophoretic separations. Optical detection methods discussed include UV/Vis absorbance, fluorescence, chemiluminescence and refractometry. Amperometry is essentially the only electrochemical detection method used in microsystems. Suppressed conductance and especially contactless conductivity (admittance) detection are in wide use for the detection of ionic analytes. Microfluidic devices, integrated to various mass spectrometers, including ESI-MS, APCI-MS, and MALDI-MS are discussed. We consider the advantages and disadvantages of each detection method and compare the best reported limits of detection in as uniform a format as the available information allows. While this review pays more attention to recent developments, our primary focus has been on the novelty and ingenuity of the approach, regardless of when it was first proposed, as long as it can be potentially relevant to miniature platforms.
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Affiliation(s)
- Cable G Warren
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, 76019-0065, United States
| | - Purnendu K Dasgupta
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, 76019-0065, United States.
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3
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Li L, Song YP, Ren DD, Li TX, Gao MH, Zhou L, Zeng ZC, Pu QA. A compact and high-performance setup of capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C 4D). Analyst 2024; 149:3034-3040. [PMID: 38624147 DOI: 10.1039/d4an00354c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) has the advantages of high throughput (simultaneous detection of multiple ions), high separation efficiency (higher than 105 theoretical plates) and rapid analysis capability (less than 5 min for common inorganic ions). A compact CE-C4D system is ideal for water quality control and on-site analysis. It is suitable not only for common cations (e.g. Na+, K+, Li+, NH4+, Ca2+, etc.) and anions (e.g. Cl-, SO42-, BrO3-, etc.) but also for some ions (e.g. lanthanide ions, Pb2+, Cd2+, etc.) that require complex derivatization procedures to be detected by ion chromatography (IC). However, an obvious limitation of the CE-C4D method is that its sensitivity (e.g. 0.3-1 μM for common inorganic ions) is often insufficient for trace analysis (e.g. 1 ppb or 20 nM level for common inorganic ions) without preconcentration. For this technology to become a powerful and routine analytical technique, the system should be made compact while maintaining trace analysis sensitivity. In this study, we developed an all-in-one version of the CE-C4D instrument with custom-made modular components to make it a convenient, compact and high-performance system. The system was designed using direct digital synthesis (DDS) technology to generate programmable sinusoidal waveforms with any frequency for excitation, a kilovolt high-voltage power supply for capillary electrophoresis separation, and an "effective" differential C4D cell with a low-noise circuitry for high-sensitivity detection. We characterized the system with different concentrations of Cs+, and even a low concentration of 20 nM was detectable without preconcentration. Moreover, the optimized CE-C4D setup was applied to analyse mixed ions at a trace concentration of 200 nM with excellent signal-to-noise ratios. In typical applications, the limits of detection based on the 3σ criterion (without baseline filtering) were 9, 10, 24, 5, and 12 nM for K+, Cs+, Li+, Ca2+, and Mg2+, respectively, and about 7, 6, 6 and 6 nM for Br-, ClO4-, BrO3- and SO42-, respectively. Finally, the setup was also applied for the analysis of all 14 lanthanide ions and rare-earth minerals, and it showed an improvement in sensitivity by more than 25 times.
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Affiliation(s)
- Lin Li
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, China.
| | - Yun-Peng Song
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, China.
| | - Dou-Dou Ren
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, China.
| | - Tang-Xiu Li
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, China.
| | - Ming-Hui Gao
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, China.
| | - Lei Zhou
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, China.
| | - Zhi-Cong Zeng
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, China.
| | - Qi-Aosheng Pu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, China.
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Novel developments in capillary electrophoresis miniaturization, sampling, detection and portability: An overview of the last decade. Trends Analyt Chem 2023. [DOI: 10.1016/j.trac.2023.116941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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5
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Nie H, Li Z, Wang X, Gu R, Yuan H, Guo Y, Xiao D. An improved dual-channel capacitively coupled contactless conductivity detector with high detection performance. Analyst 2022; 147:2106-2114. [PMID: 35470820 DOI: 10.1039/d2an00330a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Conductivity detectors are widely used electrochemical sensors. It has long been a goal of researchers to improve detection performance. In this contribution, we propose a multi-input capacitively coupled contactless conductivity detector (MIC4D) with high sensitivity, and we carry out a detailed theoretical investigation of the detector. In order to overcome the problem of a rising baseline level as a result of sensitivity improvements when using the multi-input detection method, we innovatively combine MIC4D with differential detection to propose a further-improved detector (DFMIC4D). The detector is composed of two channels, one for the reference and the other for the analyte. The signal output from differential amplification can effectively reduce the high baseline level and detection interference. In KCl solution with a concentration range of 10-4 to 10-5 M, the response to the solution is a linear function of the logarithm of the concentration, and this detector has a high slope. The slope of DFMIC4D is 1.393, higher than a traditional single-input capacitively coupled contactless conductivity detector (C4D: 0.905) and a double-input capacitively coupled contactless conductivity detector (DIC4D: 1.314). For 10-3 M KCl solution, the response-to-baseline ratio is 1.776 for C4D, 1.779 for DIC4D, and 12.06 for DFMIC4D, with a ratio increase of nearly 6-fold shown by our new detector. At a S/N (signal-to-noise) ratio of 3, the limit of detection (LOD) of DFMIC4D is low, reaching 0.7 nM. In addition, DFMIC4D can be applied to the detection of low-conductivity solutions and total dissolved solids (TDS) analysis. Compared with a standard conductivity meter, our detector shows better detection performance.
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Affiliation(s)
- Hongyu Nie
- College of Chemistry, Sichuan University, Chengdu 610064, China.
| | - Zhihui Li
- College of Chemistry, Sichuan University, Chengdu 610064, China.
| | - Xiaokun Wang
- College of Chemical Engineering, Sichuan University, Chengdu 610064, China.
| | - Rongmeng Gu
- College of Chemical Engineering, Sichuan University, Chengdu 610064, China.
| | - Hongyan Yuan
- College of Chemical Engineering, Sichuan University, Chengdu 610064, China.
| | - Yong Guo
- College of Chemistry, Sichuan University, Chengdu 610064, China.
| | - Dan Xiao
- College of Chemistry, Sichuan University, Chengdu 610064, China. .,College of Chemical Engineering, Sichuan University, Chengdu 610064, China.
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6
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A Novel Planar Grounded Capacitively Coupled Contactless Conductivity Detector for Microchip Electrophoresis. MICROMACHINES 2022; 13:mi13030394. [PMID: 35334684 PMCID: PMC8953769 DOI: 10.3390/mi13030394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 02/19/2022] [Accepted: 02/25/2022] [Indexed: 11/30/2022]
Abstract
In the microchip electrophoresis with capacitively coupled contactless conductivity detection, the stray capacitance of the detector causes high background noise, which seriously affects the sensitivity and stability of the detection system. To reduce the effect, a novel design of planar grounded capacitively coupled contactless conductivity detector (PG-C4D) based on printed circuit board (PCB) is proposed. The entire circuit plane except the sensing electrodes is covered by the ground electrode, greatly reducing the stray capacitance. The efficacy of the design has been verified by the electrical field simulation and the electrophoresis detection experiments of inorganic ions. The baseline intensity of the PG-C4D was less than 1/6 of that of the traditional C4D. The PG-C4D with the new design also demonstrated a good repeatability of migration time, peak area, and peak height (n = 5, relative standard deviation, RSD ≤ 0.3%, 3%, and 4%, respectively), and good linear coefficients within the range of 0.05–0.75 mM (R2 ≥ 0.986). The detection sensitivity of K+, Na+, and Li+ reached 0.05, 0.1, and 0.1 mM respectively. Those results prove that the new design is an effective and economical approach which can improve sensitivity and repeatability of a PCB based PG-C4D, which indicate a great application potential in agricultural and environmental monitoring.
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Tobolkina E, Rudaz S. Capillary Electrophoresis Instruments for Medical Applications and Falsified Drug Analysis/Quality Control in Developing Countries. Anal Chem 2021; 93:8107-8115. [PMID: 34061489 DOI: 10.1021/acs.analchem.1c00839] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The implementation of integrated analytical techniques to meet stringent requirements in the life sciences requires a well-developed analytical capacity. New technology in analytical equipment for the analysis of large and small molecules is continuously being developed. However, developing countries frequently struggle to keep pace with technological advancements. Hence, it is of utmost importance to better invest in optimizing existing and proven methodologies to tackle life-saving challenges in developing countries. In this regard, capillary electrophoresis is a promising candidate for solving multiple analytical problems compared to its chromatographic and spectroscopic counterparts due to its fast analytical response time and notable cost efficiency. In the following, we summarize various issues and opportunities for capillary electrophoresis to be the technique of choice for the unresolved bottlenecks in analytical equipment in developing countries for drug quality control. This perspective demonstrates that the ongoing quest for the design of new, impactful analytical techniques is a dynamic and rapidly developing research area and mentions some directions and opportunities that have arisen during the recent pandemic.
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Affiliation(s)
- Elena Tobolkina
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, CH-1211 Geneva 4, Switzerland
| | - Serge Rudaz
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, CH-1211 Geneva 4, Switzerland
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8
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Furter JS, Boillat MA, Hauser PC. Low-cost automated capillary electrophoresis instrument assembled from commercially available parts. Electrophoresis 2020; 41:2075-2082. [PMID: 32895993 DOI: 10.1002/elps.202000211] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 01/15/2023]
Abstract
A CE instrument that can be assembled from commercially available components with minimal construction effort is described. Except for the electronic control circuitry no specially made parts are required. It is based on a flexible design of microfluidic, electropneumatic, and electronic sections and different configurations can easily be implemented. Automated injection into the capillary is performed hydrodynamically by the application of a pressure for a controlled length of time. The performance of the device was tested with a contactless conductivity detector by separating different metal ions. In addition, nine metal cations related to the quality of honey were separated in 2.3 min and four honey samples were analysed quantitatively to demonstrate the applicability of the method.
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Affiliation(s)
- Jasmine S Furter
- Department of Chemistry, University of Basel, Basel, Switzerland
| | | | - Peter C Hauser
- Department of Chemistry, University of Basel, Basel, Switzerland
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9
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Determination of the alcoholic content in whiskeys using micellar electrokinetic chromatography on microchips. Food Chem 2020; 329:127175. [PMID: 32516708 DOI: 10.1016/j.foodchem.2020.127175] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 05/25/2020] [Accepted: 05/26/2020] [Indexed: 01/31/2023]
Abstract
This report describes the development of a methodology based on micellar electrokinetic chromatography for the separation of alcohols on chip-based systems aiming the determination of alcoholic content in whiskey samples. The separation conditions were optimized the best results were achieved using 50 mmolL-1 phosphate buffer containing 30 mmolL-1 sodium dodecyl sulfate. The alcoholic content was determined in 16 seized whiskey samples from 4 different brands as well as in the original samples. The methodology presented herein allowed the correct classification of 75% of the seized samples as adulterated and the data obtained did not statistically differ from those recorded by a reference technique. The proposed analytical approach emerges as a promising tool to provide a rapid screening of the beverages authenticity and it may be useful to be widely explored for the quality control.
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10
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Hauser PC, Kubáň P. Capacitively coupled contactless conductivity detection for analytical techniques - Developments from 2018 to 2020. J Chromatogr A 2020; 1632:461616. [PMID: 33096295 DOI: 10.1016/j.chroma.2020.461616] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/09/2020] [Accepted: 10/10/2020] [Indexed: 12/20/2022]
Abstract
The developments of analytical contactless conductivity measurements based on capacitive coupling over the two years from mid-2018 to mid-2020 are covered. This mostly concerns applications of the technique in zone electrophoresis employing conventional capillaries and to a lesser extent lab-on-chip devices. However, its use for the detection in several other flow-based analytical methods has also been reported. Detection of bubbles and measurements of flow rates in two-phase flows are also recurring themes. A few new applications in stagnant aqueous samples, e.g. endpoint detection in titrations and measurement on paper-based devices, have been reported. Some variations of the design of the measuring cells and their read-out electronics have also been described.
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Affiliation(s)
- Peter C Hauser
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056, Basel, Switzerland.
| | - Pavel Kubáň
- Institute of Analytical Chemistry of the Czech Academy of Sciences, Veveří 97, CZ-60200, Brno, Czech Republic.
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11
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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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12
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Wang C, Xing H, Zheng B, Yuan H, Xiao D. Simulation and Experimental Study on Doubled-Input Capacitively Coupled Contactless Conductivity Detection of Capillary Electrophoresis. Sci Rep 2020; 10:7944. [PMID: 32409736 PMCID: PMC7224287 DOI: 10.1038/s41598-020-64896-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 03/26/2020] [Indexed: 11/08/2022] Open
Abstract
In this contribution, we optimize the structure of double-input capacitively coupled contactless conductivity detector (DIC4D) that proposed before by our group and successfully applied it in the capillary electrophoresis of inorganic ion analysis. Furthermore, we present the detail theoretical analysis and simulation to exploring the working mechanism of DIC4D. Compared with C4D, under identical experimental conditions and by using the same current-to-voltage converter, both the theoretical and experimental results suggest that the effectiveness and feasibility of DIC4D. The improved DIC4D diminished the baseline drift effects in C4D, provides lower noise, higher sensitivity and notably stable baseline. The LODs of DIC4D are 1.0 μM for K+ and 1.5 μM for Li+ (S/N = 3). DIC4D provides a better linear relationship (R = 0.997 and 0.998 for K+ and Li+, respectively) with the range of 2.0 μM ~ 2.5 mM.
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Affiliation(s)
- Chunling Wang
- College of Chemical Engineering, Sichuan University, Chengdu, 610064, People's Republic of China
| | - Haoyang Xing
- College of Physical Science and Technology, Sichuan University, Chengdu, 610065, People's Republic of China
| | - Baozhan Zheng
- College of Chemistry, Sichuan University, Chengdu, 610065, People's Republic of China
| | - Hongyan Yuan
- College of Chemical Engineering, Sichuan University, Chengdu, 610064, People's Republic of China.
| | - Dan Xiao
- College of Chemical Engineering, Sichuan University, Chengdu, 610064, People's Republic of China.
- College of Chemistry, Sichuan University, Chengdu, 610065, People's Republic of China.
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13
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Tang XY, Huang J, Ji H, Wang B, Huang Z. New method for bubble/slug velocity measurement in small channels. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:055001. [PMID: 32486734 DOI: 10.1063/1.5134548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 04/14/2020] [Indexed: 06/11/2023]
Abstract
Based on the C4D technique and cross correlation velocity measurement technique, a new method for bubble/slug velocity measurement of the gas-liquid two-phase flow in small channels is proposed. A new C4D sensor, which is suitable for the parameter measurement of the gas-liquid two-phase flow in small channels, is developed by introducing the principle of capacitive reactance elimination. With two new C4D sensors, a bubble/slug velocity measurement system is developed, and the bubble/slug velocity is determined by the cross correlation velocity measurement technique. To verify the effectiveness of the proposed bubble/slug velocity measurement method, three prototypes of bubble/slug velocity measurement systems with different diameters (1.82 mm, 2.65 mm, and 2.96 mm, respectively) were established, and the bubble/slug measurement experiments were carried out. The research results show that the capacitive reactance elimination is an effective way to overcome the unfavorable influence of the coupled capacitances on measurement results. The experimental results indicate that the proposed method can successfully realize the bubble/slug velocity measurement in small channels, and the velocity measurement accuracy is satisfactory. For the three prototypes of the bubble/slug velocity measurement system, the maximum relative errors of the bubble/slug velocity measurement are all less than 5%.
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Affiliation(s)
- Xiao-Yu Tang
- State Key Laboratory of Industrial Control Technology, College of Control Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Junchao Huang
- State Key Laboratory of Industrial Control Technology, College of Control Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Haifeng Ji
- State Key Laboratory of Industrial Control Technology, College of Control Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Baoliang Wang
- State Key Laboratory of Industrial Control Technology, College of Control Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Zhiyao Huang
- State Key Laboratory of Industrial Control Technology, College of Control Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
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14
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Beutner A, Herl T, Matysik FM. Selectivity enhancement in capillary electrophoresis by means of two-dimensional separation or dual detection concepts. Anal Chim Acta 2018; 1057:18-35. [PMID: 30832915 DOI: 10.1016/j.aca.2018.11.042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 11/01/2018] [Accepted: 11/19/2018] [Indexed: 12/18/2022]
Abstract
For the identification and quantification of analytes in complex samples, highly selective analytical strategies are required. The selectivity of single separation techniques such as gas chromatography (GC), liquid chromatography (LC), or capillary electrophoresis (CE) with common detection principles can be enhanced by hyphenating orthogonal separation techniques but also by using complementary detection systems. In this review, two-dimensional systems containing CE in at least one dimension are reviewed, namely LC-CE or 2D CE systems. Particular attention is paid to the aspect of selectivity enhancement due to the orthogonality of the different separation mechanisms. As an alternative concept, dual detection approaches are reviewed using the common detectors of CE such as UV/VIS, laser-induced fluorescence, capacitively coupled contactless conductivity (C4D), electrochemical detection, and mass spectrometry. Special emphasis is given to dual detection systems implementing the highly flexible C4D as one detection component. Selectivity enhancement can be achieved in case of complementarity of the different detection techniques.
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Affiliation(s)
- Andrea Beutner
- Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, Universitaetsstrasse 31, 93053, Regensburg, Germany
| | - Thomas Herl
- Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, Universitaetsstrasse 31, 93053, Regensburg, Germany
| | - Frank-Michael Matysik
- Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, Universitaetsstrasse 31, 93053, Regensburg, Germany.
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15
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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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16
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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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17
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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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18
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Vu AP, Nguyen TN, Do TT, Doan TH, Ha TH, Ta TT, Nguyen HL, Hauser PC, Nguyen TAH, Mai TD. Clinical screening of paraquat in plasma samples using capillary electrophoresis with contactless conductivity detection: Towards rapid diagnosis and therapeutic treatment of acute paraquat poisoning in Vietnam. J Chromatogr B Analyt Technol Biomed Life Sci 2017; 1060:111-117. [PMID: 28609698 DOI: 10.1016/j.jchromb.2017.06.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Revised: 05/26/2017] [Accepted: 06/05/2017] [Indexed: 10/19/2022]
Abstract
The employment of a purpose-made capillary electrophoresis (CE) instrument with capacitively coupled contactless conductivity detection (C4D) as a simple and cost-effective solution for clinical screening of paraquat in plasma samples for early-stage diagnosis of acute herbicide poisoning is reported. Paraquat was determined using an electrolyte composed of 10mM histidine adjusted to pH 4 with acetic acid. A detection limit of 0.5mg/L was achieved. Good agreement between results from CE-C4D and the confirmation method (HPLC-UV) was obtained, with relative errors for the two pairs of data better than 20% for 31 samples taken from paraquat-intoxicated patients. The results were used by medical doctors for identification and prognosis of acute paraquat poisoning cases. The objective of the work is the deployment of the developed approach in rural areas in Vietnam as a low-cost solution to reduce the mortality rate due to accidental or suicidal ingestion of paraquat.
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Affiliation(s)
- Anh Phuong Vu
- Poison Control Center, Bach Mai Hospital, 78 Giai Phong road, Dong Da, Hanoi, Viet Nam; Department of Analytical Chemistry, Faculty of Chemistry, VNU University of Science, Vietnam National University, Hanoi - 19 Le Thanh Tong, Hanoi, Viet Nam(1)
| | - Thi Ngan Nguyen
- Poison Control Center, Bach Mai Hospital, 78 Giai Phong road, Dong Da, Hanoi, Viet Nam; Department of Analytical Chemistry, Faculty of Chemistry, VNU University of Science, Vietnam National University, Hanoi - 19 Le Thanh Tong, Hanoi, Viet Nam(1)
| | - Thi Trang Do
- Poison Control Center, Bach Mai Hospital, 78 Giai Phong road, Dong Da, Hanoi, Viet Nam; Department of Analytical Chemistry, Faculty of Chemistry, VNU University of Science, Vietnam National University, Hanoi - 19 Le Thanh Tong, Hanoi, Viet Nam(1)
| | - Thu Ha Doan
- Poison Control Center, Bach Mai Hospital, 78 Giai Phong road, Dong Da, Hanoi, Viet Nam
| | - Tran Hung Ha
- Poison Control Center, Bach Mai Hospital, 78 Giai Phong road, Dong Da, Hanoi, Viet Nam
| | - Thi Thao Ta
- Department of Analytical Chemistry, Faculty of Chemistry, VNU University of Science, Vietnam National University, Hanoi - 19 Le Thanh Tong, Hanoi, Viet Nam(1)
| | - Hung Long Nguyen
- Vietnam Food Administration, Ministry of Health, 138A Giang Vo, Ba Đinh, Hanoi, Viet Nam
| | - Peter C Hauser
- University of Basel, Department of Chemistry, Spitalstrasse 51, 4056 Basel, Switzerland
| | - Thi Anh Huong Nguyen
- Department of Analytical Chemistry, Faculty of Chemistry, VNU University of Science, Vietnam National University, Hanoi - 19 Le Thanh Tong, Hanoi, Viet Nam(1).
| | - Thanh Duc Mai
- PNAS, Institut Galien de Paris-Sud, Faculté de Pharmacie, Université Paris-Sud, CNRS, 5 rue JB Clément, 92296 Châtenay-Malabry, France.
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Rezende KCA, Moreira RC, Logrado LPL, Talhavini M, Coltro WKT. Authenticity screening of seized whiskey samples using electrophoresis microchips coupled with contactless conductivity detection. Electrophoresis 2016; 37:2891-2895. [DOI: 10.1002/elps.201600277] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/04/2016] [Accepted: 08/05/2016] [Indexed: 02/01/2023]
Affiliation(s)
| | - Roger Cardoso Moreira
- Instituto de Química, Universidade Federal de Goiás; Campus Samambaia; Goiânia GO Brazil
| | | | - Márcio Talhavini
- Instituto Nacional de Criminalística; Departamento de Polícia Federal; Brasília DF Brazil
| | - Wendell K. T. Coltro
- Instituto de Química, Universidade Federal de Goiás; Campus Samambaia; Goiânia GO Brazil
- Instituto Nacional de Ciência e Tecnologia em Bioanalítica (INCTBio); Campinas SP Brazil
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Simultaneous determination of rare earth elements in ore and anti-corrosion coating samples using a portable capillary electrophoresis instrument with contactless conductivity detection. J Chromatogr A 2016; 1457:151-8. [DOI: 10.1016/j.chroma.2016.06.050] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 06/08/2016] [Accepted: 06/15/2016] [Indexed: 11/20/2022]
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21
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Cabot JM, Duffy E, Currivan S, Ruland A, Jalili R, Mozer AJ, Innis PC, Wallace GG, Breadmore M, Paull B. Characterisation of graphene fibres and graphene coated fibres using capacitively coupled contactless conductivity detector. Analyst 2016; 141:2774-82. [DOI: 10.1039/c5an02534f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The use of capacitively coupled contactless conductivity detection (C4D) for the characterisation of thin conductive graphene fibres, graphene composite fibres, and graphene coated fibrous materials is demonstrated for the first time.
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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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23
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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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