1
|
Hu C, Xie B, Li H, Xiao D. A five-electrode capacitively coupled contactless conductivity detector with a low limit of detection. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2023; 15:2253-2261. [PMID: 37128967 DOI: 10.1039/d3ay00328k] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The conductivity detector is a broadly used device that allows for the highly efficient detection of analytes, and continuous efforts have been directed toward lowering the limit of detection. In this study, a five-electrode capacitively coupled contactless conductivity detector (TIC4D) is proposed, which uses copper mesh between the electrodes for a grounding shield to reduce the interference of stray capacitance and noise. After adding the copper mesh shield, the difference value between the response signal and baseline at low KCl concentration is effectively increased, achieving 33 mV for 10-9 M KCl solution. Meanwhile, for the unshielded detector, the difference is only 18 mV for the KCl solution at the same concentration. The response signal shows a linear function of the logarithm at the range of 10-4 M to 10-5 M KCl solution, and the TIC4D detector displays a higher slope (0.8448) than the conventional single-input capacitively coupled contactless conductivity detector (C4D: 0.5579) and dual-input capacitively coupled contactless conductivity detectors (DIC4D: 0.6173). Moreover, two TIC4D detectors are combined to achieve a dual-channel six-input differential capacitively coupled contactless conductivity detector (SIDC4D), reducing the high baseline levels caused by the multi-signal input. By differentially amplifying the output signal, the high baseline levels and noise interference can be effectively reduced. For the 10-3 M KCl solution, the ratio of the response signal to baseline for SIDC4D can reach 8.500, almost 7 times that of TIC4D, and a lower limit of detection (LOD) of 3 × 10-10 M is also achieved. This work may open a new door based on coupled contactless conductivity for detection performance.
Collapse
Affiliation(s)
- Chunqiong Hu
- College of Chemical Engineering, Sichuan University, Chengdu 610064, China.
| | - Bo Xie
- College of Chemical Engineering, Sichuan University, Chengdu 610064, China.
| | - Hongmei Li
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Dan Xiao
- College of Chemical Engineering, Sichuan University, Chengdu 610064, China.
- College of Chemistry, Sichuan University, Chengdu 610064, China
| |
Collapse
|
2
|
Li P, Li S, Yuan D, Lin K. On-site and high-resolution spectrophotometric measurement of total dissolved sulfide in natural waters. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 863:160919. [PMID: 36529398 DOI: 10.1016/j.scitotenv.2022.160919] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/10/2022] [Accepted: 12/10/2022] [Indexed: 06/17/2023]
Abstract
Reliable high-resolution data is essential for understanding the aquatic sulfur biogeochemical processes. However, the accurate quantification of total dissolved sulfide (TDS) remains challenging due to its low concentration and vulnerability to oxidation. Furthermore, the frequency and the spatial coverage of TDS measurements are constrained by the cost of the laboratory analysis. In this study, an automated portable system was developed for on-site real-time measurement of trace TDS in natural waters. This system was based on the classic methylene blue (MB) spectrophotometric assay combined with on-line solid phase extraction (SPE) and flow injection analysis (FIA). A commercially available weak-cation-exchange cartridge was used as the SPE sorbent. Experimental parameters affecting the performance of the proposed system were optimized. Under the optimized conditions, linear calibration range of 0.02-2.50 μmol L-1 was obtained with a sample loading volume of 5.0 mL and a sample throughput of 12 h-1. The limit of detection could be lowered to 0.003 μmol L-1 by pre-concentrating 10.0 mL sample. The precision, determined as the relative standard deviation (RSD), was <2.75 % (n = 11) and the recoveries from spiked samples ranged from 54.4 % to 97.5 % with RSDs of 1.1-2.3 % (n = 3). Furthermore, the FIA-SPE-MB system was successfully deployed in the Taihu Lake for continuous 48 h monitoring of variations in TDS, demonstrating the applicability of this system for on-site TDS measurement in natural waters.
Collapse
Affiliation(s)
- Peng Li
- Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Xiamen 361102, PR China; College of the Environment and Ecology, Xiamen University, Xiamen 361102, PR China
| | - Songtao Li
- Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Xiamen 361102, PR China; College of the Environment and Ecology, Xiamen University, Xiamen 361102, PR China
| | - Dongxing Yuan
- Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Xiamen 361102, PR China; College of the Environment and Ecology, Xiamen University, Xiamen 361102, PR China
| | - Kunde Lin
- Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Xiamen 361102, PR China; College of the Environment and Ecology, Xiamen University, Xiamen 361102, PR China.
| |
Collapse
|
3
|
Simultaneous determination of volatile phenol, cyanide, anionic surfactant, and ammonia nitrogen in drinking water by a continuous flow analyzer. Sci Rep 2023; 13:1829. [PMID: 36725871 PMCID: PMC9892590 DOI: 10.1038/s41598-023-28776-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 01/24/2023] [Indexed: 02/03/2023] Open
Abstract
This study developed a method for the simultaneous determination of volatile phenol, cyanide, anionic surfactant, and ammonia nitrogen in drinking water, using a continuous flow analyzer. The samples were first distilled at 145 °C. The phenol in the distillate then subsequently reacted with alkaline ferricyanide and 4-aminoantipyrine to form a red complex that was measured colorimetrically at 505 nm. Cyanide in the distillate subsequently reacted with chloramine T to form cyanogen chloride, which then formed a blue complex with pyridinecarboxylic acid that was measured colorimetrically at 630 nm. The anionic surfactant reacted with basic methylene blue to form a compound that was extracted into chloroform and washed with acidic methylene blue to remove interfering substances. The blue compound in chloroform was determined colorimetrically at 660 nm. Ammonia reacted with salicylate and chlorine from dichloroisocyanuric acid to produce indophenol blue at 37 °C in an alkaline environment that was measured at 660 nm. The relative standard deviations were 0.75-6.10% and 0.36-5.41%, respectively, and the recoveries were 96.2-103.6% and 96.0-102.4% when the mass concentration of volatile phenol and cyanide was in the range of 2-100 μg/L. The linear correlation coefficients were ≥ 0.9999, and the detection limits were1.2 μg/L and 0.9 μg/L, respectively. The relative standard deviations were 0.27-4.86% and 0.33-5.39%, and the recoveries were 93.7-107.0% and 94.4-101.7%. When the mass concentration of anionic surfactant and ammonia nitrogen was 10-1000 μg/L. The linear correlation coefficients were 0.9995 and 0.9999, and the detection limits were 10.7 μg/L and 7.3 μg/L, respectively. When compared to the national standard method, no statistically significant difference was found. This approach saves time and labor, has a lower detection limit, higher precision and accuracy, less contamination, and is more appropriate for the analysis and determination of large-volume samples.
Collapse
|
4
|
Phouthavong V, Inoue H, Phomkeona K, Chounlamany V. Home-Made Membraneless Vaporization Gas-Liquid Separator for Colorimetric Determination of Ethanol in Alcoholic Beverages. JOURNAL OF ANALYTICAL METHODS IN CHEMISTRY 2022; 2022:7346253. [PMID: 35402059 PMCID: PMC8989598 DOI: 10.1155/2022/7346253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 03/08/2022] [Accepted: 03/21/2022] [Indexed: 06/14/2023]
Abstract
This work utilized the simplicity of a so-called membraneless vaporization (MBL-VP) unit as a gas separator for the colorimetric determination of ethanol in alcoholic beverages. A beverage sample with a volume of 1 mL was directly injected into a small container which was hung from a lid inside a closed 40 mL reused glass bottle without pretreatment such as distillation. An acidified potassium dichromate (Cr2O7 2-) acceptor solution, preadded to the glass bottle, was reduced to Chromium (III) ion by the diffusion of vaporized ethanol from the sample. After 5 min, the absorbing solution was collected for colorimetric detection at 590 nm. The unit manually quantifies ethanol in the range 1.0-90% (v/v) with satisfactory interday precision but without matrix effect (recovery 89-109%). The method was validated with the conventional distillation/pycnometer method which showed no significant difference of ethanol contents between those two methods and the declared values of 12 alcoholic beverages, indicating sufficient accuracy. Analyses of alcoholic beverages using this method were successful with benefits of simplicity, cheapness, and less energy consumption.
Collapse
Affiliation(s)
- Vanpaseuth Phouthavong
- Department of Chemistry, Faculty of Natural Sciences, National University of Laos, P.O. Box 7322, Vientiane, Laos
| | - Hayato Inoue
- Department of Environmental and Life Sciences, Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, Aichi 441-8580, Japan
| | - Kesiny Phomkeona
- Department of Chemistry, Faculty of Natural Sciences, National University of Laos, P.O. Box 7322, Vientiane, Laos
| | - Vanseng Chounlamany
- Department of Chemistry, Faculty of Natural Sciences, National University of Laos, P.O. Box 7322, Vientiane, Laos
| |
Collapse
|
5
|
Trojanowicz M, Pyszynska M. Flow-Injection Methods in Water Analysis-Recent Developments. Molecules 2022; 27:1410. [PMID: 35209198 PMCID: PMC8879103 DOI: 10.3390/molecules27041410] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 02/11/2022] [Accepted: 02/15/2022] [Indexed: 12/10/2022] Open
Abstract
Widespread demand for the analysis and control of water quality and supply for human activity and ecosystem sustainability has necessitated the continuous improvement of water analysis methods in terms of their reliability, efficiency, and costs. To satisfy these requirements, flow-injection analysis using different detection methods has successfully been developed in recent decades. This review, based on about 100 original research papers, presents the achievements in this field over the past ten years. Various methodologies for establishing flow-injection measurements are reviewed, together with microfluidics and portable systems. The developed applications mostly concern not only the determination of inorganic analytes but also the speciation analysis of different elements, and the determination of several total indices of water quality. Examples of the determination of organic residues (e.g., pesticides, phenolic compounds, and surfactants) in natural surface waters, seawater, groundwater, and drinking water have also been identified. Usually, changes in the format of manual procedures for flow-injection determination results in the improvement of various operational parameters, such as the limits of detection, the sampling rate, or selectivity in different matrices.
Collapse
Affiliation(s)
- Marek Trojanowicz
- Laboratory of Nuclear Analytical Methods, Institute of Nuclear Chemistry and Technology, Dorodna 16, 02-195 Warsaw, Poland;
- Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Marta Pyszynska
- Laboratory of Nuclear Analytical Methods, Institute of Nuclear Chemistry and Technology, Dorodna 16, 02-195 Warsaw, Poland;
| |
Collapse
|
6
|
Nawalohakul T, Charoenjiraroj P, Chantiwas R, Wilairat P, Praditweangkum W. A ninety-six well plate as headspaces with moist starch indicator paper as a cover for the determination of ascorbic acid by iodate oxidation and formation of volatile iodine. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2022; 14:741-749. [PMID: 35108716 DOI: 10.1039/d1ay02050a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
This work presents the use of a 96-well plate as headspaces for the determination of ascorbic acid in samples loaded in the 96-well plate. Ascorbic acid in the sample is oxidized to iodide by the addition of excess acidic iodate solution into the well. The iodide is further oxidized by the remaining iodate to molecular iodine. A single sheet of moist starch indicator paper is immediately placed over the 96-well plate after the addition of the iodate with the moisture forming a gas seal. The iodine gas in each well diffuses through the headspace to react with the starch paper producing circular areas of a colored starch-iodine complex. After 15 min the indicator paper is scanned, and the digital images of the complex are analyzed by using ImageJ software to obtain blue intensity values. The precision of the intensity values from 12 wells containing 20 μL of 2.84 mM standard ascorbic acid is <2% relative standard deviation. Optimal conditions for detection were investigated, including the starch concentration, the acidic iodate reagent, and the measurement time. The linear calibration range of ascorbic acid is 0.284-2.84 mM, based on the plot of concentration vs. -log(reflectance). The coefficient of determination (r2) is >0.998. Samples of fruit juice and dietary supplements were analyzed for their ascorbic acid contents. The results obtained from the headspace reflectance method are not statistically different from values obtained from the titration method using paired t-tests (α = 0.05).
Collapse
Affiliation(s)
- Thichaphat Nawalohakul
- Department of Chemistry, School of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand.
| | - Pannarat Charoenjiraroj
- Department of Chemistry, School of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand.
| | - Rattikan Chantiwas
- Department of Chemistry, Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Rama VI Rd, Bangkok 10400, Thailand
| | - Prapin Wilairat
- Analytical Sciences and National Doping Test Institute, Mahidol University, Rama VI Rd, Bangkok 10400, Thailand
| | - Wiboon Praditweangkum
- Department of Chemistry, School of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand.
| |
Collapse
|
7
|
Vidigal SSMP, Rangel AOSS. Exploiting Flow-Based Separation Techniques for Sample Handling in Wine Analysis. FOOD ANAL METHOD 2021. [DOI: 10.1007/s12161-021-02138-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
8
|
Wang T, Huang Y, Xu J, Guo W, Yuan D. Development and application of a shipboard method for spectrophotometric determination of nanomolar dissolved sulfide in estuarine surface waters using reverse flow injection analysis coupled with a long path length liquid waveguide capillary cell. Microchem J 2021. [DOI: 10.1016/j.microc.2021.106522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
9
|
Ratanawimarnwong N, Ruckchang P, Yooram S, Songsrirote K, Uraisin K, Cerdà V. Development of a microfluidic membraneless vaporization flow system for trace analysis of arsenic. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2021; 13:202-211. [PMID: 33331839 DOI: 10.1039/d0ay01970d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A new design of a membraneless vaporization (MBL-VP) unit coupled with a specific flow system is presented for the determination of arsenic at trace levels using a hydride generation process. The MBL-VP unit contains two concentric conical reservoirs, with the outer cone selected as the donor reservoir. The volume of the outer donor reservoir is thereby greater than the acceptor volume, necessary for holding sufficient sample and reagents for the generation of arsine gas by reaction between As(iii) and sodium borohydride under acidic conditions. The arsine gas diffuses into the narrow headspace and is absorbed by an aliquot of 150 μL of mercuric chloride acceptor solution. The resulting reaction produces hydronium ions which is monitored by the absorbance change at 530 nm of the methyl orange indicator added in the acceptor solution. To decrease the detection limit, the aspiration and removal of the donor plug, comprising the sample, borohydride and acid, into and out of the donor cone are repeated several times, while the acceptor solution is kept unchanged. As a result, analysis of arsenic was achieved in the range of 10 to 100 μg L-1 with a detection limit of 8 μg L-1. Application to surface water was investigated. Percent recoveries of spiked surface water samples were in the range of 94-110%. For comparison of total arsenic (As(iii) and As(v)), the results obtained from the developed method are not statistically different from the ICP-OES method.
Collapse
Affiliation(s)
- Nuanlaor Ratanawimarnwong
- Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit 23, Bangkok 10110, Thailand. and Flow Innovation-Research for Science and Technology Laboratories (Firstlabs), Thailand
| | - Patcharat Ruckchang
- Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit 23, Bangkok 10110, Thailand.
| | - Supattra Yooram
- Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit 23, Bangkok 10110, Thailand.
| | - Kriangsak Songsrirote
- Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit 23, Bangkok 10110, Thailand.
| | - Kanchana Uraisin
- Flow Innovation-Research for Science and Technology Laboratories (Firstlabs), Thailand and Department of Chemistry, Center of the Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Victor Cerdà
- Department of Chemistry, University of the Balearic Islands, 07122 Palma de Mallorca, Spain
| |
Collapse
|
10
|
Mulec AO, Mladenovič A, Pranjić AM, Oprčkal P, Ščančar J, Milačič R. Study of interferences and procedures for their removal in the spectrophotometric determination of ammonium and selected anions in coloured wastewater samples. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2020; 12:4769-4782. [PMID: 32940268 DOI: 10.1039/d0ay01361g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Ammonium and selected anions were determined in wastewater samples with highly complex matrices by spectrophotometry using the reagent-kit method. For this purpose, the interferents of coloured compounds and S2-, SO32-, CO32- and Cl-, which are often present in wastewater samples, were systematically investigated in the spectrophotometric determination of ammonium, nitrate, chloride, sulphate, fluoride and phosphate. After this, innovative procedures for their removal were proposed. For sample decolourization, a DEAE column was used to determine ammonium, while a Florisil column was used for the colour removal and anions' determination. S2- and CO32- were eliminated from the samples by adding HCl or HNO3, which transformed them into gases H2S and CO2. The stepwise addition of CaCl2 to the sample, adjusted to pH 8, initiated the formation of CaSO3, which was removed by filtration. Cl- was removed by the addition of Ag2O, which formed a AgCl precipitate that was removed from the solution by filtration. The accuracy of the determination was tested with spike-recovery tests, which showed recoveries for the analytes in the spiked samples ranging from 95 to 105%. The repeatability of the measurements of nitrate, chloride, sulphate and phosphate in the wastewater samples was better than ±1%, while that for the ammonium and fluoride samples was ±2 and ±5%, respectively. The data from the present investigation revealed that the developed procedures for the decolourization and stepwise removal of interferents enabled accurate spectrophotometric determination of ammonium, nitrate, chloride, sulphate, fluoride and phosphate by using cuvette tests in complex wastewater and environmental water samples.
Collapse
Affiliation(s)
- Andreea Oarga Mulec
- Department of Materials, Slovenian National Building and Civil Engineering Institute, Dimičeva 12, 1000 Ljubljana, Slovenia
| | | | | | | | | | | |
Collapse
|
11
|
Elbashir AA, Elgorashe REE, Alnajjar AO, Aboul-Enein HY. Application of Capillary Electrophoresis with Capacitively Coupled Contactless Conductivity Detection (CE-C 4D): 2017-2020. Crit Rev Anal Chem 2020; 52:535-543. [PMID: 32835492 DOI: 10.1080/10408347.2020.1809340] [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] [Indexed: 10/23/2022]
Abstract
Capacitively coupled contactless conductivity detection (C4D) has emerged as influential to detect analytes that do not have chromogenic or fluorogenic functional group. Since our last review several new capillary electrophoresis (CE) methods coupled with (CE-C4D) have been communicated. The aim of this review is to give an update of the almost all the new applications of CE-C4D in the field of pharmaceutical, food and biomedical analysis covering the period from 2017 to April 2020. The utilization of CE with C4D in the areas of pharmaceutical, food and biomedical analysis is presented. Finally, concluding remarks and outlooks are discussed.
Collapse
Affiliation(s)
- Abdalla Ahmed Elbashir
- Department of Chemistry, College of Science, King Faisal University, Al Ahsa, Saudi Arabia
| | | | - Ahmed O Alnajjar
- Department of Chemistry, College of Science, King Faisal University, Al Ahsa, Saudi Arabia
| | - Hassan Y Aboul-Enein
- Pharmaceutical and Medicinal Chemistry Department, Pharmaceutical and Drug Industries Research Division, National Research Centre, Cairo, Egypt
| |
Collapse
|
12
|
Ayuning Tyas A, Sonsa-ard T, Uraisin K, Nacapricha D, Saetear P. Simple Flow-Based System with an In-Line Membrane Gas-liquid Separation Unit and a Contactless Conductivity Detector for the Direct Determination of Sulfite in Clear and Turbid Food Samples. MEMBRANES 2020; 10:membranes10050104. [PMID: 32443480 PMCID: PMC7281478 DOI: 10.3390/membranes10050104] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 05/11/2020] [Accepted: 05/14/2020] [Indexed: 11/17/2022]
Abstract
This study presents a simple flow-based system for the determination of the preservative agent sulfite in food and beverages. The standard method of conversion of sulfite ions into SO2 gas by acidification is employed to separate the sulfite from sample matrices. The sample is aspirated into a donor stream of sulfuric acid. A membrane gas–liquid separation unit, also called a ‘gas-diffusion (GD)’ unit, incorporating a polytetrafluoroethylene (PTFE) hydrophobic membrane allows the generated gas to diffuse into a stream of deionized water in the acceptor line. The dissolution of the SO2 gas leads to a change in the conductivity of water which is monitored by an in-line capacitively coupled contactless conductivity detector (C4D). The conductivity change is proportional to the concentration of sulfite in the sample. In this work, both clear (wine) and turbid (fruit juice and extracts of dried fruit) were selected to demonstrate the versatility of the developed method. The method can tolerate turbidity up to 60 Nephelometric Turbidity Units (NTUs). The linear range is 5–25 mg L−1 SO32− with precision <2% RSD. The flow system employs a peristaltic pump for propelling all liquid lines. Quantitative results of sulfite were statistically comparable to those obtained from iodimetric titration for the wine samples.
Collapse
|
13
|
Mantim T, Chaisiwamongkhol K, Uraisin K, Hauser PC, Wilairat P, Nacapricha D. Dual-Purpose Photometric-Conductivity Detector for Simultaneous and Sequential Measurements in Flow Analysis. Molecules 2020; 25:E2284. [PMID: 32414012 PMCID: PMC7287826 DOI: 10.3390/molecules25102284] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 04/27/2020] [Accepted: 05/07/2020] [Indexed: 01/29/2023] Open
Abstract
This work presents a new dual-purpose detector for photometric and conductivity measurements in flow-based analysis. The photometric detector is a paired emitter-detector diode (PEDD) device, whilst the conductivity detection employs a capacitively coupled contactless conductivity detector (C4D). The flow-through detection cell is a rectangular acrylic block (ca. 2 × 2 × 1.5 cm) with cylindrical channels in Z-configuration. For the PEDD detector, the LED light source and detector are installed inside the acrylic block. The two electrodes of the C4D are silver conducting ink painted on the PEEK inlet and outlet tubing of the Z-flow cell. The dual-purpose detector is coupled with a sequential injection analysis (SIA) system for simultaneous detection of the absorbance of the orange dye and conductivity of the dissolved oral rehydration salt powder. The detector was also used for sequential measurements of creatinine and the conductivity of human urine samples. The creatinine analysis is based on colorimetric detection of the Jaffé reaction using the PEDD detector, and the conductivity of the urine, as measured by the C4D detector, is expressed in millisiemens (mS cm-1).
Collapse
Affiliation(s)
- Thitirat Mantim
- Flow Innovation-Research for Science and Technology Laboratories (FIRST Labs), Bangkok 10400, Thailand; (K.C.); (K.U.); (P.W.)
- Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumwit 23 Road, Bangkok 10110, Thailand
- Center of Excellence for Innovation in Chemistry and Department of Chemistry, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
| | - Korbua Chaisiwamongkhol
- Flow Innovation-Research for Science and Technology Laboratories (FIRST Labs), Bangkok 10400, Thailand; (K.C.); (K.U.); (P.W.)
- School of Science, Mae Fah Luang University, Chiang Rai 57100, Thailand
- Center of Chemical Innovation for Sustainability (CIS), Mae Fah Luang University, Chiang Rai 57100, Thailand
| | - Kanchana Uraisin
- Flow Innovation-Research for Science and Technology Laboratories (FIRST Labs), Bangkok 10400, Thailand; (K.C.); (K.U.); (P.W.)
- Center of Excellence for Innovation in Chemistry and Department of Chemistry, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
| | - Peter C. Hauser
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland;
| | - Prapin Wilairat
- Flow Innovation-Research for Science and Technology Laboratories (FIRST Labs), Bangkok 10400, Thailand; (K.C.); (K.U.); (P.W.)
- National Doping Control Centre, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
| | - Duangjai Nacapricha
- Flow Innovation-Research for Science and Technology Laboratories (FIRST Labs), Bangkok 10400, Thailand; (K.C.); (K.U.); (P.W.)
- Center of Excellence for Innovation in Chemistry and Department of Chemistry, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
| |
Collapse
|
14
|
Micro-PAD card for measuring total ammonia nitrogen in saliva. Anal Bioanal Chem 2020; 412:3167-3176. [PMID: 32303795 DOI: 10.1007/s00216-020-02577-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 02/24/2020] [Accepted: 03/03/2020] [Indexed: 10/24/2022]
Abstract
This work presents a portable microfluidic paper-based analytical device (micro-PAD) card for the quantification of total ammonia nitrogen in human saliva. The amount of total ammonia nitrogen in saliva can be an indicator of the status of the oral microbiome with potential correlation to kidney health problems. The developed micro-PAD card comprises twenty units consisting of three stacked layers of circular discs: the sample layer, paper discs impregnated with sodium hydroxide solution, the PTFE membrane layer, and the detection layer, paper discs impregnated with bromothymol blue. The twenty units were aligned on transparent laminating pouches laminated to form the micro-PAD card (7.5 cm × 10.5 cm). Saliva samples can be directly dispensed onto the micro-PAD card and the detection was achieved by the BTB indicator color change, from yellow to blue, after conversion of ammonium into ammonia and diffusion of the ammonia gas through a hydrophobic layer. The determination of total ammonia nitrogen in saliva using the developed micro-PAD card intended to be very simple method and operated without the need of laboratory equipment. A quantification limit of 11.3 NH4+mg L-1 and linear application range from up to 150 NH4+mg L-1 were obtained making it suitable for the expected concentrations of total ammonia nitrogen in human saliva. It was successfully applied to saliva samples and its validation obtained by comparison against a potentiometric method. The card is stable for at least 1 month making it ideal as a portable device for point-of-care diagnosis. Graphical Abstract.
Collapse
|
15
|
Automatic On-Line Purge-and-Trap Sequential Injection Analysis for Trace Ammonium Determination in Untreated Estuarine and Seawater Samples. Molecules 2020; 25:molecules25071569. [PMID: 32235335 PMCID: PMC7180869 DOI: 10.3390/molecules25071569] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 03/25/2020] [Accepted: 03/27/2020] [Indexed: 11/22/2022] Open
Abstract
An innovative automatic purge-and-trap (P&T) system coupled with fluorimetric sequential injection (SI), for the on-line separation and preconcentration of volatile compounds, is presented. The truth of concept is demonstrated for the ammonium fluorimetric determination in environmental water samples with complex matrices without any pretreatment. The P&T flow system comprises a thermostated purge-vessel where ammonium is converted into gaseous ammonia and a trap-vessel for ammonia collection. This configuration results in matrix removal as well as analyte preconcentration, avoiding membrane-associated problems. All the main parameters affecting the efficiency of a P&T system were studied and optimized. The proposed method is characterized by a working range of 2.7–150.0 μg L−1 of NH4+, with a detection and quantification limit of 0.80 and 2.66 μg L−1, respectively, for a 10-mL sample consumption. The accuracy of the method was assessed by recovery assays in seawater, estuarine, and lake water samples as well as by the analysis of standard reference material.
Collapse
|
16
|
Kraikaew P, Pluangklang T, Ratanawimarnwong N, Uraisin K, Wilairat P, Mantim T, Nacapricha D. Simultaneous determination of ethanol and total sulfite in white wine using on-line cone reservoirs membraneless gas-liquid separation flow system. Microchem J 2019. [DOI: 10.1016/j.microc.2019.104007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|
17
|
Li P, Deng Y, Shu H, Lin K, Chen N, Jiang Y, Chen J, Yuan D, Ma J. High-frequency underway analysis of ammonium in coastal waters using an integrated syringe-pump-based environmental-water analyzer (iSEA). Talanta 2019; 195:638-646. [DOI: 10.1016/j.talanta.2018.11.108] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 11/28/2018] [Accepted: 11/29/2018] [Indexed: 12/16/2022]
|
18
|
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.
Collapse
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
| |
Collapse
|
19
|
Giakisikli G, Anthemidis AN. Automatic pressure-assisted dual-headspace gas-liquid microextraction. Lab-in-syringe platform for membraneless gas separation of ammonia coupled with fluorimetric sequential injection analysis. Anal Chim Acta 2018; 1033:73-80. [PMID: 30172334 DOI: 10.1016/j.aca.2018.06.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/08/2018] [Accepted: 06/12/2018] [Indexed: 02/03/2023]
Abstract
A novel pressure-assisted dual-headspace lab-in-syringe microextraction technique is presented as an alternative approach for automatic on-line membraneless gas separation of volatile compounds. The developed gas-liquid microextraction procedure is based on the lab-in-syringe (LIS) concept by using two independent micro-syringe pumps which are connected to each other for the application of negative and positive pressure inside the common headspace area of the syringe barrels. The adoption of reduced and increased pressure conditions is facilitated by the programmable LIS strategy resulting in increased extraction rates. The analytical process includes the in-situ ammonia vapor generation in the headspace of the first microsyringe, under reduced pressure environment, and its subsequent transportation into the headspace of the second microsyringe. Then, positive pressure is applied inside the second microsyringe enabling the ammonia vapor dissolution into the extraction solution to produce a fluorescent product (isoindol-1-sulfonat). The reaction is time and temperature affected, thus after an optimized time of delay inside the thermostated syringe barrel at 60 °C, it is delivered into the flow-cell of the miniSIA system where it is quantified at 425 nm (excitation wavelength, 365 nm). The proposed preconcentration system has been fully tested and optimized regarding the relevant parameters affecting the generation of gaseous ammonia, its effective transportation into the headspace of the second syringe barrel and its quantitative dissolution and reaction with the extraction solution. For a sample volume of 3000 μL, the sample frequency is 8 h-1, the precision expressed as relative standard deviation (RSD) is 3.6 (at 5.0 μg L-1) and a detection limit (3s) of 0.05 μg L-1 for ammonium is obtained. The detection is linear in the concentration range of 0.15 and 10.0 μg L-1 with a correlation coefficient of 0.9987. The accuracy of the proposed method has been evaluated by analyzing a standard reference material (relative error: 3.8%) as well as using the Certified Method (relative error < 5.5%) for ammonium determination. The potential of this novel schema has been demonstrated for ammonia determination in natural water samples.
Collapse
Affiliation(s)
- Georgia Giakisikli
- Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University, Thessaloniki 54124, Greece
| | - Aristidis N Anthemidis
- Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University, Thessaloniki 54124, Greece.
| |
Collapse
|
20
|
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]
|