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Barros VAF, Zagatto EAG. Relevant insights and concepts overlooked throughout the development of flow analysis. A tutorial. Talanta 2024; 280:126689. [PMID: 39153255 DOI: 10.1016/j.talanta.2024.126689] [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: 04/19/2024] [Revised: 07/26/2024] [Accepted: 08/06/2024] [Indexed: 08/19/2024]
Abstract
The conceptual expansion, fast development, and general acceptance of flow analysis are consequence of its adherence to the principles of green and white analytical chemistry, and chemical derivatization plays an essential role in this context. Through the flow analysis development, however, some of its potentialities and limitations have been overlooked. This is more evident when the involved modifications in flow rates, timing and/or manifold architecture deteriorate the analytical signals. These aspects have not always been systematically investigated, and are addressed here in relation to flow analyzers with UV-Vis spectrophotometric detection. Novel strategies for solution handling, guidance for dealing with the aforementioned analytical signal deterioration, and an alternative possibility for exploiting differential aspiration are presented. The concept of blank reagent carrier stream is proposed.
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Affiliation(s)
- Valdemir A F Barros
- Centre for Nuclear Energy in Agriculture, University of Sao Paulo, P.O. Box 96, Piracicaba, 13400-970, Brazil
| | - Elias A G Zagatto
- Centre for Nuclear Energy in Agriculture, University of Sao Paulo, P.O. Box 96, Piracicaba, 13400-970, Brazil.
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2
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Kimoto H, Hirahara Y, Sato K, Iiyama M, Hashimoto T, Hayashita T. High-throughput determination of lipopolysaccharide by flow injection analysis using dipicolylamine-type fluorescent probe. TALANTA OPEN 2023. [DOI: 10.1016/j.talo.2023.100204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023] Open
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3
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Condensed Phase Membrane Introduction Mass Spectrometry: A Direct Alternative to Fully Exploit the Mass Spectrometry Potential in Environmental Sample Analysis. SEPARATIONS 2023. [DOI: 10.3390/separations10020139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
Membrane introduction mass spectrometry (MIMS) is a direct mass spectrometry technique used to monitor online chemical systems or quickly quantify trace levels of different groups of compounds in complex matrices without extensive sample preparation steps and chromatographic separation. MIMS utilizes a thin, semi-permeable, and selective membrane that directly connects the sample and the mass spectrometer. The analytes in the sample are pre-concentrated by the membrane depending on their physicochemical properties and directly transferred, using different acceptor phases (gas, liquid or vacuum) to the mass spectrometer. Condensed phase (CP) MIMS use a liquid as a medium, extending the range to new applications to less-volatile compounds that are challenging or unsuitable to gas-phase MIMS. It directly allows the rapid quantification of selected compounds in complex matrices, the online monitoring of chemical reactions (in real-time), as well as in situ measurements. CP-MIMS has expanded beyond the measurement of several organic compounds because of the use of different types of liquid acceptor phases, geometries, dimensions, and mass spectrometers. This review surveys advancements of CP-MIMS and its applications to several molecules and matrices over the past 15 years.
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Altahan MF, Esposito M, Achterberg EP. Improvement of On-Site Sensor for Simultaneous Determination of Phosphate, Silicic Acid, Nitrate plus Nitrite in Seawater. SENSORS (BASEL, SWITZERLAND) 2022; 22:3479. [PMID: 35591168 PMCID: PMC9104159 DOI: 10.3390/s22093479] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/27/2022] [Accepted: 04/29/2022] [Indexed: 02/05/2023]
Abstract
Accurate, on-site determinations of macronutrients (phosphate (PO43-), nitrate (NO3-), and silicic acid (H4SiO4)) in seawater in real time are essential to obtain information on their distribution, flux, and role in marine biogeochemical cycles. The development of robust sensors for long-term on-site analysis of macronutrients in seawater is a great challenge. Here, we present improvements of a commercial automated sensor for nutrients (including PO43-, H4SiO4, and NO2- plus NO3-), suitable for a variety of aquatic environments. The sensor uses the phosphomolybdate blue method for PO43-, the silicomolybdate blue method for H4SiO4 and the Griess reagent method for NO2-, modified with vanadium chloride as reducing agent for the determination of NO3-. Here, we report the optimization of analytical conditions, including reaction time for PO43- analysis, complexation time for H4SiO4 analysis, and analyte to reagent ratio for NO3- analysis. The instrument showed wide linear ranges, from 0.2 to 100 μM PO43-, between 0.2 and 100 μM H4SiO4, from 0.5 to 100 μM NO3-, and between 0.4 and 100 μM NO2-, with detection limits of 0.18 μM, 0.15 μM, 0.45 μM, and 0.35 μM for PO43-, H4SiO4, NO3-, and NO2-, respectively. The analyzer showed good precision with a relative standard deviation of 8.9% for PO43-, 4.8% for H4SiO4, and 7.4% for NO2- plus NO3- during routine analysis of certified reference materials (KANSO, Japan). The analyzer performed well in the field during a 46-day deployment on a pontoon in the Kiel Fjord (located in the southwestern Baltic Sea), with a water supply from a depth of 1 m. The system successfully collected 443, 440, and 409 on-site data points for PO43-, Σ(NO3- + NO2-), and H4SiO4, respectively. Time series data agreed well with data obtained from the analysis of discretely collected samples using standard reference laboratory procedures and showed clear correlations with key hydrographic parameters throughout the deployment period.
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Affiliation(s)
- Mahmoud Fatehy Altahan
- GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Germany;
- Central Laboratory for Environmental Quality Monitoring, National Water Research Center, El-Qanater El-Khairia 13621, Egypt
| | - Mario Esposito
- GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Germany;
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Cooray AT, Pullin MJ. Ferrozine colorimetry and reverse flow injection analysis (rFIA) based method for the determination of total iron in aqueous solutions at nanomolar concentrations. J INDIAN CHEM SOC 2022. [DOI: 10.1016/j.jics.2022.100541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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6
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Rocha FRP, Zagatto EAG. Chemical Derivatization in Flow Analysis. Molecules 2022; 27:1563. [PMID: 35268664 PMCID: PMC8912107 DOI: 10.3390/molecules27051563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/17/2022] [Accepted: 02/24/2022] [Indexed: 11/16/2022] Open
Abstract
Chemical derivatization for improving selectivity and/or sensitivity is a common practice in analytical chemistry. It is particularly attractive in flow analysis in view of its highly reproducible reagent addition(s) and controlled timing. Then, measurements without attaining the steady state, kinetic discrimination, exploitation of unstable reagents and/or products, as well as strategies compliant with Green Analytical Chemistry, have been efficiently exploited. Flow-based chemical derivatization has been accomplished by different approaches, most involving flow and manifold programming. Solid-phase reagents, novel strategies for sample insertion and reagent addition, as well as to increase sample residence time have been also exploited. However, the required alterations in flow rates and/or manifold geometry may lead to spurious signals (e.g., Schlieren effect) resulting in distorted peaks and a noisy/drifty baseline. These anomalies can be circumvented by a proper flow system design. In this review, these aspects are critically discussed mostly in relation to spectrophotometric and luminometric detection.
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Affiliation(s)
| | - Elias A. G. Zagatto
- Center for Nuclear Energy in Agriculture, University of Sao Paulo, Piracicaba 13416-000, Brazil;
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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: 10] [Impact Index Per Article: 5.0] [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.
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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;
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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]
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Chen L, Xu J, Wang T, Huang Y, Yuan D, Gong Z. Toward a versatile flow technique: Development and application of reverse flow dual-injection analysis (rFDIA) for determining dissolved iron redox species and soluble reactive phosphorus in seawater. Talanta 2021; 232:122404. [PMID: 34074395 DOI: 10.1016/j.talanta.2021.122404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/28/2021] [Accepted: 04/02/2021] [Indexed: 11/26/2022]
Abstract
A versatile flow analyzer that extended the features of reverse flow injection analysis (rFIA) was developed in this study and named reverse flow dual-injection analysis (rFDIA). Compared with typical rFIA, the analyzer requires less reagent and is more environmentally friendly, which has two injection valves and two reagent loops for the accurate and successive injection of two reagents. With a 2-m long liquid waveguide capillary cell (LWCC) and a spectrophotometer, the analyzer was applied to underway determination of dissolved iron redox species in estuarine and coastal waters. Detection limits of 0.18 and 0.20 nmol L-1 were achieved for Fe(II) and Fe(II + III), respectively and a linear dynamic range of 0.5-450 nmol L-1 was obtained for both Fe(II) and Fe(II + III). The sample throughput for the simultaneous measurement of Fe(II) and Fe(II + III) was 12 h-1, and each analysis consumed only 8 mL sample, 520 μL ferrozine solution, and 260 μL ascorbic acid solution. The analyzer was also used to measure nanomolar amounts of soluble reactive phosphorus (SRP) in seawater. The detection limit and the linear dynamic range for the SRP assay were 0.5 nmol L-1 and 1.5-850 nmol L-1. For SRP determination, the sample throughput was 20 h-1, and each analysis required 9 mL of sample, 130 μL of mixed reagent solution and 260 μL of ascorbic acid. The analytical results were reproducible, with a relative standard deviation of 1.4% (2.5 nmol L-1, n = 10), 2.1% (2.5 nmol L-1, n = 10), and 2.1% (10 nmol L-1, n = 11) for Fe(II), Fe(II + III), and SRP, respectively.
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Affiliation(s)
- Luodan Chen
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China; College of the Environment and Ecology, Xiamen University, Xiamen, China
| | - Jin Xu
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China; College of the Environment and Ecology, Xiamen University, Xiamen, China
| | - Ting Wang
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China; College of the Environment and Ecology, Xiamen University, Xiamen, China
| | - Yongming Huang
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
| | - Dongxing Yuan
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China; College of the Environment and Ecology, Xiamen University, Xiamen, China
| | - Zhenbin Gong
- College of the Environment and Ecology, Xiamen University, Xiamen, China
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10
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New intelligent photometric titration system and its method for constructing chemical oxygen demand based on micro-flow injection. Microchem J 2018. [DOI: 10.1016/j.microc.2018.08.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Palamy S, Ruengsitagoon W. Reverse flow injection spectrophotometric determination of ciprofloxacin in pharmaceuticals using iron from soil as a green reagent. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 190:129-134. [PMID: 28922638 DOI: 10.1016/j.saa.2017.09.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/22/2017] [Accepted: 09/12/2017] [Indexed: 06/07/2023]
Abstract
A novel reverse flow injection spectrophotometric method for the determination of ciprofloxacin was successfully combined with the on-line introduction of an iron solution extracted from soil as green reagent. The assay was optimized by a univariate method to select the optimum conditions for the highest absorbance and highest stability of the complex. Beer-Lambert's law (λmax=440nm) is obeyed in the range 0.5-50μgmL-1 with a correlation coefficient (r2) of 0.9976 and 0.9996 using soil as green reagent from Khon Kaen, Thailand and Vientiane, Laos, respectively. The average percentage recoveries were in the range of 98.55-102.14% and the precision was in the range of 0.80-1.73%. The limit of detection and the limit of quantitation were 0.20 and 0.69μgmL-1, respectively, with a sampling rate of over 46samplesh-1. The method was successfully applied to the determination of ciprofloxacin in commercial pharmaceutical formulations. The results were in good agreement with those obtained by the reference HPLC method using a t-test at 95% of confidence level for comparison. This method is suitable for laboratories looking for alternative analytical methods using green reagents.
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Affiliation(s)
- Sysay Palamy
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Wirat Ruengsitagoon
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand.
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12
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A catalytic spectrophotometric method for determination of nanomolar manganese in seawater using reverse flow injection analysis and a long path length liquid waveguide capillary cell. Talanta 2018; 178:577-582. [DOI: 10.1016/j.talanta.2017.09.073] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 09/21/2017] [Accepted: 09/26/2017] [Indexed: 12/31/2022]
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13
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Youngvises N, Suwannasaroj K, Jakmunee J, AlSuhaimi A. Multi-reverse flow injection analysis integrated with multi-optical sensor for simultaneous determination of Mn(II), Fe(II), Cu(II) and Fe(III) in natural waters. Talanta 2016; 166:369-374. [PMID: 28213248 DOI: 10.1016/j.talanta.2016.01.052] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/24/2016] [Accepted: 01/25/2016] [Indexed: 11/25/2022]
Abstract
Multi-reverse flow injection analysis (Mr-FIA) integrated with multi-optical sensor was developed and optimized for the simultaneous determination of multi ions; Mn(II), Fe(II), Cu(II) and Fe(III) in water samples. The sample/standard solutions were propelled making use of a four channels peristaltic pump whereas 4 colorimetric reagents specific for the metal ions were separately injected in sample streams using multi-syringe pump. The color zones that formed in the individual mixing coils were then streamed into multi-channels spectrometer, which comprised of four flows through cell and four pairs of light emitting diode and photodiode, whereby signals were measured concurrently. The linearity range (along with detection limit, µgL-1) was 0.050-3.0(16), 0.30-2.0 (11), 0.050-1.0(12) and 0.10-1.0(50)mgL-1, for Mn(II), Fe(II), Cu(II) and Fe(III), respectively. In the interim, the correlation coefficients were 0.9924-0.9942. The percentages relative standard deviation was less than 3. The proposed system was applied successfully to determine targeted metal ions simultaneously in natural water with high sample throughput and low reagent consumption, thus it satisfies the criteria of Green Analytical Chemistry (GAC) and its goals.
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Affiliation(s)
- Napaporn Youngvises
- Department of Chemistry and Innovative Green Chemistry Research Unit, Faculty of Science and Technology, Thammasat University, Pathum Thani 12120, Thailand.
| | - Kittigan Suwannasaroj
- Department of Chemistry and Innovative Green Chemistry Research Unit, Faculty of Science and Technology, Thammasat University, Pathum Thani 12120, Thailand
| | - Jaroon Jakmunee
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Awadh AlSuhaimi
- Department of Chemistry, Faculty of Science, Taibah University, Prince Naif Road, AlMadeinah AlMunwaraha 42353, Saudi Arabia
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Abstract
A dynamic development of methodologies of analytical flow injection measurements during four decades since their invention has reinforced the solid position of flow analysis in the arsenal of techniques and instrumentation of contemporary chemical analysis.
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Affiliation(s)
- Marek Trojanowicz
- Laboratory of Nuclear Analytical Methods
- Institute of Nuclear Chemistry and Technology
- 03-195 Warsaw
- Poland
- Department of Chemistry
| | - Kamila Kołacińska
- Laboratory of Nuclear Analytical Methods
- Institute of Nuclear Chemistry and Technology
- 03-195 Warsaw
- Poland
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15
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Elsuccary S, Salem AA. Novel flow injection analysis methods for the determination of total iron in blood serum and water. Talanta 2015; 131:108-15. [DOI: 10.1016/j.talanta.2014.07.068] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Revised: 07/21/2014] [Accepted: 07/21/2014] [Indexed: 11/15/2022]
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16
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Biscay J, González García MB, Costa García A. Electrochemical biotin detection based on magnetic beads and a new magnetic flow cell for screen printed electrode. Talanta 2014; 131:706-11. [PMID: 25281162 DOI: 10.1016/j.talanta.2014.08.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 08/03/2014] [Accepted: 08/05/2014] [Indexed: 12/16/2022]
Abstract
The use of the first flow-cell for magnetic assays with an integrated magnet is reported here. The flow injection analysis system (FIA) is used for biotin determination. The reaction scheme is based on a one step competitive assay between free biotin and biotin labeled with horseradish peroxidase (B-HRP). The mixture of magnetic beads modified with streptavidin (Strep-MB), biotin and B-HRP is left 15 min under stirring and then a washing step is performed. After that, 100 μL of the mixture is injected and after 30s 100 μL of 3,3',5,5'-Tetramethylbenzidine (TMB) is injected and the FIAgram is recorded applying a potential of -0.2V. The linear range obtained is from 0.01 to 1 nM of biotin and the sensitivity is 758 nA/nM. The modification and cleaning of the electrode are performed in an easy way due to the internal magnet of the flow cell.
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Affiliation(s)
- Julien Biscay
- Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, 33006 Oviedo, Spain
| | - María Begoña González García
- Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, 33006 Oviedo, Spain
| | - Agustín Costa García
- Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, 33006 Oviedo, Spain.
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Biscay J, Begoña González García M, García AC. Flow Injection Analysis System Using Magnetic Beads, Screen Printed Electrodes and Magnets. ELECTROANAL 2014. [DOI: 10.1002/elan.201400212] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abstract
Point-of-care applications are gaining increasing interest in clinical diagnostics and emergency applications. Biosensors are used to monitor the biomolecular interaction process between a disease biomarker and a recognition element such as a reagent. Essential are the quality and selectivity of the recognition elements and assay types used to improve sensitivity and to avoid nonspecific interactions. In addition, quality measures are influenced by the detection principle and the evaluation strategies. For these reasons, this review provides a survey and validation of recognition elements, assays, and various types of detection methods for point-of-care testing (POCT) platforms. Common applications of clinical parameters are discussed and considered. In this ever-changing field, a snapshot of current applications is needed. We provide such a snapshot by way of a table including literature citations and also discuss these applications in more detail throughout.
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Affiliation(s)
- Günter Gauglitz
- Institute of Physical and Theoretical Chemistry, University of Tuebingen, D-72076 Tuebingen, Germany;
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Peixoto PS, Tóth IV. Increased Sensitivity Spectrophotometric Flow Analysis Method for Copper Determination in Water Samples. ANAL LETT 2013. [DOI: 10.1080/00032719.2013.821655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Feng S, Zhang M, Huang Y, Yuan D, Zhu Y. Simultaneous determination of nanomolar nitrite and nitrate in seawater using reverse flow injection analysis coupled with a long path length liquid waveguide capillary cell. Talanta 2013; 117:456-62. [DOI: 10.1016/j.talanta.2013.09.042] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 09/20/2013] [Accepted: 09/22/2013] [Indexed: 11/25/2022]
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21
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Nacapricha D, Sastranurak P, Mantim T, Amornthammarong N, Uraisin K, Boonpanaid C, Chuyprasartwattana C, Wilairat P. Cross injection analysis: Concept and operation for simultaneous injection of sample and reagents in flow analysis. Talanta 2013; 110:89-95. [DOI: 10.1016/j.talanta.2013.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Revised: 02/06/2013] [Accepted: 02/06/2013] [Indexed: 11/25/2022]
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Łękawska-Andrinopoulou L, Vasiliou EG, Georgakopoulos DG, Yialouris CP, Georgiou CA. Rapid enzymatic method for pectin methyl esters determination. JOURNAL OF ANALYTICAL METHODS IN CHEMISTRY 2013; 2013:854763. [PMID: 24455426 PMCID: PMC3888753 DOI: 10.1155/2013/854763] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 12/03/2013] [Accepted: 12/04/2013] [Indexed: 05/08/2023]
Abstract
Pectin is a natural polysaccharide used in food and pharma industries. Pectin degree of methylation is an important parameter having significant influence on pectin applications. A rapid, fully automated, kinetic flow method for determination of pectin methyl esters has been developed. The method is based on a lab-made analyzer using the reverse flow-injection/stopped flow principle. Methanol is released from pectin by pectin methylesterase in the first mixing coil. Enzyme working solution is injected further downstream and it is mixed with pectin/pectin methylesterase stream in the second mixing coil. Methanol is oxidized by alcohol oxidase releasing formaldehyde and hydrogen peroxide. This reaction is coupled to horse radish peroxidase catalyzed reaction, which gives the colored product 4-N-(p-benzoquinoneimine)-antipyrine. Reaction rate is proportional to methanol concentration and it is followed using Ocean Optics USB 2000+ spectrophotometer. The analyzer is fully regulated by a lab written LabVIEW program. The detection limit was 1.47 mM with an analysis rate of 7 samples h(-1). A paired t-test with results from manual method showed that the automated method results are equivalent to the manual method at the 95% confidence interval. The developed method is rapid and sustainable and it is the first application of flow analysis in pectin analysis.
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Affiliation(s)
| | | | | | | | - Constantinos A. Georgiou
- Chemistry, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece
- *Constantinos A. Georgiou:
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