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Li M, Xu Y, Men J, Yan C, Tang H, Zhang T, Li H. Hybrid variable selection strategy coupled with random forest (RF) for quantitative analysis of methanol in methanol-gasoline via Raman spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 251:119430. [PMID: 33485240 DOI: 10.1016/j.saa.2021.119430] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/23/2020] [Accepted: 01/03/2021] [Indexed: 06/12/2023]
Abstract
With the trend of portable and miniaturization, Raman spectrometer requires more advanced analytical methods providing more rapid and accurate analysis performance for in-situ analysis. In this work, a hybrid variable selection method based on V-WSP and variable importance measurement (VIM) coupled with random forest (RF) was used to improve the quantitative analysis performance of portable laser Raman instruments for quantitative analysis of methanol content in methanol gasoline. First, five preprocessing methods were applied to reduce the infection information in the raw spectra, respectively. Based on the spectra data processed by multivariate scattering correction (MSC), V-WSP was employed to filter the infection or redundant information in Raman spectroscopy, and 579 variables were obtained when the correlation threshold is 0.9600. Then, the variables were further eliminated by VIM. Finally, 43 variables were obtained by the V-WSP-VIM method. In data processing, out of bag (OOB) error estimation and 10-flod cross validation (CV) were applied to optimize the parameters of preprocessing methods, V-WSP, VIM and RF model. The results fully demonstrated that compared with the RF model based on raw spectra, the RF model based on V-WSP-VIM method can achieve a better prediction performance for the quantitative analysis of methanol content in methanol-gasoline, with the coefficients of determination of cross-validation (R2CV) improving from 0.9100 to 0.9662, the root mean square error of cross-validation (RMSECV) reducing from 0.0572 to 0.0365%, the coefficients of determination of prediction set (R2P) improving from 0.9214 to 0.9407, the root mean square error of prediction set (RMSEP) reducing from 0.0420 to 0.0382%, the variables reducing from 1044 to 43 and the modeling time reducing from 72.94 to 6.41 s. The results indicates that V-WSP-VIM coupled with RF is an effective method to improve the performance of portable laser Raman spectrometer for quantitative analysis of methanol content in methanol gasoline.
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Affiliation(s)
- Maogang Li
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi'an, 710127, China
| | - Yanyan Xu
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi'an, 710127, China
| | - Jing Men
- Xi'an WanLong Pharmaceutical Co., Ltd., Xi'an, 710119, China
| | - Chunhua Yan
- College of Chemistry and Chemical Engineering, Xi'an Shiyou University, Xi'an, 710065, China
| | - Hongsheng Tang
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi'an, 710127, China.
| | - Tianlong Zhang
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi'an, 710127, China
| | - Hua Li
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi'an, 710127, China; College of Chemistry and Chemical Engineering, Xi'an Shiyou University, Xi'an, 710065, China.
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Silwana B, Van Der Horst C, Iwuoha E, Somerset V. A brief review on recent developments of electrochemical sensors in environmental application for PGMs. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2016; 51:1233-1247. [PMID: 27715654 DOI: 10.1080/10934529.2016.1212562] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This study offers a brief review of the latest developments and applications of electrochemical sensors for the detection of Platinum Group Metals (PGMs) using electrochemical sensors. In particular, significant advances in electrochemical sensors made over the past decade and sensing methodologies associated with the introduction of nanostructures are highlighted. Amongst a variety of detection methods that have been developed for PGMs, nanoparticles offer the unrivaled merits of high sensitivity. Rapid detection of PGMs is a key step to promote improvement of the public health and individual quality of life. Conventional methods to detect PGMs rely on time-consuming and labor intensive procedures such as extraction, isolation, enrichment, counting, etc., prior to measurement. This results in laborious sample preparation and testing over several days. This study reviewed the state-of-the-art application of nanoparticles (NPs) in electrochemical analysis of environmental pollutants. This review is intended to provide environmental scientists and engineers an overview of current rapid detection methods, a close look at the nanoparticles based electrodes and identification of knowledge gaps and future research needs. We summarize electrodes that have been used in the past for detection of PGMs. We describe several examples of applications in environmental electrochemical sensors and performance in terms of sensitivity and selectivity for all the sensors utilized for PGMs detection. NPs have promising potential to increase competitiveness of electrochemical sensors in environmental monitoring, though this review has focused mainly on sensors used in the past decade for PGMs detection. This review therefore provides a synthesis of outstanding performances in recent advances in the nanosensor application for PGMs determination.
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Affiliation(s)
- Bongiwe Silwana
- a Natural Resources and the Environment (NRE), Council for Scientific and Industrial Research (CSIR) , Stellenbosch , South Africa
- b SensorLab , Department of Chemistry , University of the Western Cape , Bellville , South Africa
| | - Charlton Van Der Horst
- a Natural Resources and the Environment (NRE), Council for Scientific and Industrial Research (CSIR) , Stellenbosch , South Africa
- b SensorLab , Department of Chemistry , University of the Western Cape , Bellville , South Africa
| | - Emmanuel Iwuoha
- b SensorLab , Department of Chemistry , University of the Western Cape , Bellville , South Africa
| | - Vernon Somerset
- a Natural Resources and the Environment (NRE), Council for Scientific and Industrial Research (CSIR) , Stellenbosch , South Africa
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3
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An Overview on the Application of Chemometrics in Food Science and Technology—An Approach to Quantitative Data Analysis. FOOD ANAL METHOD 2016. [DOI: 10.1007/s12161-016-0574-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Silwana B, van der Horst C, Iwuoha E, Somerset V. Reduced Graphene Oxide Impregnated Antimony Nanoparticle Sensor for Electroanalysis of Platinum Group Metals. ELECTROANAL 2016. [DOI: 10.1002/elan.201501071] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Bongiwe Silwana
- SensorLab, Department of Chemistry; University of the Western Cape; Bellville 7535 South Africa
- Natural Resources and the Environment (NRE); Council for Scientific and Industrial Research (CSIR); Stellenbosch 7600 South Africa
| | - Charlton van der Horst
- SensorLab, Department of Chemistry; University of the Western Cape; Bellville 7535 South Africa
- Natural Resources and the Environment (NRE); Council for Scientific and Industrial Research (CSIR); Stellenbosch 7600 South Africa
| | - Emmanuel Iwuoha
- SensorLab, Department of Chemistry; University of the Western Cape; Bellville 7535 South Africa
| | - Vernon Somerset
- Natural Resources and the Environment (NRE); Council for Scientific and Industrial Research (CSIR); Stellenbosch 7600 South Africa
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5
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Bioelectronic tongues: New trends and applications in water and food analysis. Biosens Bioelectron 2015; 79:608-26. [PMID: 26761617 DOI: 10.1016/j.bios.2015.12.075] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Revised: 12/11/2015] [Accepted: 12/21/2015] [Indexed: 11/23/2022]
Abstract
Over the last years, there has been an increasing demand for fast, highly sensitive and selective methods of analysis to meet new challenges in environmental monitoring, food safety and public health. In response to this demand, biosensors have arisen as a promising tool, which offers accurate chemical data in a timely and cost-effective manner. However, the difficulty to obtain sensors with appropriate selectivity and sensitivity for a given analyte, and to solve analytical problems which do not require the quantification of a certain analyte, but an overall effect on a biological system (e.g. toxicity, quality indices, provenance, freshness, etc.), led to the concept of electronic tongues as a new strategy to tackle these problems. In this direction, to improve the performance of electronic tongues, and thus to spawn new application fields, biosensors have recently been incorporated to electronic tongue arrays, leading to what is known as bioelectronic tongues. Bioelectronic tongues provide superior performance by combining the capabilities of electronic tongues to derive meaning from complex or imprecise data, and the high selectivity and specificity of biosensors. The result is postulated as a tool that exploits chemometrics to solve biosensors' interference problems, and biosensors to solve electronic tongues' selectivity problems. The review presented herein aims to illustrate the capabilities of bioelectronic tongues as analytical tools, especially suited for screening analysis, with particular emphasis in water analysis and the characterization of food and beverages. After briefly reviewing the key concepts related to the design and principles of electronic tongues, we provide an overview of significant contributions to the field of bioelectronic tongues and their future perspectives.
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Hayat A, Marty JL. Disposable screen printed electrochemical sensors: tools for environmental monitoring. SENSORS (BASEL, SWITZERLAND) 2014; 14:10432-53. [PMID: 24932865 PMCID: PMC4118360 DOI: 10.3390/s140610432] [Citation(s) in RCA: 170] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Revised: 06/03/2014] [Accepted: 06/05/2014] [Indexed: 12/04/2022]
Abstract
Screen printing technology is a widely used technique for the fabrication of electrochemical sensors. This methodology is likely to underpin the progressive drive towards miniaturized, sensitive and portable devices, and has already established its route from "lab-to-market" for a plethora of sensors. The application of these sensors for analysis of environmental samples has been the major focus of research in this field. As a consequence, this work will focus on recent important advances in the design and fabrication of disposable screen printed sensors for the electrochemical detection of environmental contaminants. Special emphasis is given on sensor fabrication methodology, operating details and performance characteristics for environmental applications.
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Affiliation(s)
- Akhtar Hayat
- Images, Universite´De Perpignan Via Domitia, 52 Avenue Paul Alduy, Perpignan Cedex 66860, France.
| | - Jean Louis Marty
- Images, Universite´De Perpignan Via Domitia, 52 Avenue Paul Alduy, Perpignan Cedex 66860, France.
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8
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Balabin RM, Smirnov SV. Interpolation and extrapolation problems of multivariate regression in analytical chemistry: benchmarking the robustness on near-infrared (NIR) spectroscopy data. Analyst 2012; 137:1604-10. [DOI: 10.1039/c2an15972d] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Nordon A, Diez-Lazaro A, Wong CWL, McGill CA, Littlejohn D, Weerasinghe M, Mamman DA, Hitchman ML, Wilkie J. Consideration of some sampling problems in the on-line analysis of batch processes by low-field NMR spectrometry. Analyst 2008; 133:339-47. [DOI: 10.1039/b714266h] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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KOMPANY-ZAREH M, KHOSHKAM M. Application of Chemometrics Methods with Kinetic Constraints for Estimation of Rate Constants of Second Order Consecutive Reactions. ANAL SCI 2008; 24:637-45. [DOI: 10.2116/analsci.24.637] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Schafer WA, Hobbs S, Rehm J, Rakestraw DA, Orella C, McLaughlin M, Ge Z, Welch CJ. Mobile Tool for HPLC Reaction Monitoring. Org Process Res Dev 2007. [DOI: 10.1021/op7000854] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wes A. Schafer
- Separation & Analysis Technologies, Merck Process Research, Rahway, New Jersey 07065, U.S.A., and Eksigent Technologies, Inc., Dublin, California 94568, U.S.A
| | - Steve Hobbs
- Separation & Analysis Technologies, Merck Process Research, Rahway, New Jersey 07065, U.S.A., and Eksigent Technologies, Inc., Dublin, California 94568, U.S.A
| | - Jason Rehm
- Separation & Analysis Technologies, Merck Process Research, Rahway, New Jersey 07065, U.S.A., and Eksigent Technologies, Inc., Dublin, California 94568, U.S.A
| | - David A. Rakestraw
- Separation & Analysis Technologies, Merck Process Research, Rahway, New Jersey 07065, U.S.A., and Eksigent Technologies, Inc., Dublin, California 94568, U.S.A
| | - Charles Orella
- Separation & Analysis Technologies, Merck Process Research, Rahway, New Jersey 07065, U.S.A., and Eksigent Technologies, Inc., Dublin, California 94568, U.S.A
| | - Mark McLaughlin
- Separation & Analysis Technologies, Merck Process Research, Rahway, New Jersey 07065, U.S.A., and Eksigent Technologies, Inc., Dublin, California 94568, U.S.A
| | - Zhihong Ge
- Separation & Analysis Technologies, Merck Process Research, Rahway, New Jersey 07065, U.S.A., and Eksigent Technologies, Inc., Dublin, California 94568, U.S.A
| | - Christopher J. Welch
- Separation & Analysis Technologies, Merck Process Research, Rahway, New Jersey 07065, U.S.A., and Eksigent Technologies, Inc., Dublin, California 94568, U.S.A
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12
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Gutiérrez M, Alegret S, del Valle M. Potentiometric bioelectronic tongue for the analysis of urea and alkaline ions in clinical samples. Biosens Bioelectron 2007; 22:2171-8. [PMID: 17097867 DOI: 10.1016/j.bios.2006.10.007] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Revised: 09/05/2006] [Accepted: 10/09/2006] [Indexed: 11/29/2022]
Abstract
Urea biosensors based on urease covalently immobilized on to ammonium and hydrogen ion-selective electrodes were included in arrays together with ammonium, potassium, sodium, hydrogen and generic response to alkaline sensors. Response models based on artificial neural network (ANN) and partial least squares (PLS1) were built, tested and compared for the simultaneous determination of urea, ammonium, potassium and sodium. The results show that it is possible to obtain good ANN and PLS calibration models for simultaneous determination of these four species, but with better prediction capability when the ANN are used. The developed bioelectronic tongue was applied to multidetermination in urine samples. The ANN model showed again better agreement with reference methods, allowing a simple direct determination of urea in the real samples without the necessity of eliminating the alkaline interferences, or compensating endogenous ammonium.
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Affiliation(s)
- Manuel Gutiérrez
- Sensors & Biosensors Group, Department of Chemistry, Autonomous University of Barcelona, 08193 Bellaterra, Catalonia, Spain
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13
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Chapter 30 Potentiometric electronic tongues applied in ion multidetermination. ELECTROCHEMICAL SENSOR ANALYSIS 2007. [DOI: 10.1016/s0166-526x(06)49030-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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14
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Kourti T. Process Analytical Technology Beyond Real-Time Analyzers: The Role of Multivariate Analysis. Crit Rev Anal Chem 2006. [DOI: 10.1080/10408340600969957] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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15
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Lim JK, Kwon O, Kang DS, Joo SW. Raman spectroscopy study and density functional theory calculations of the nematic liquid crystal 4-n-pentyl-4′-cyanobiphenyl under an electric field. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.03.055] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Plum A, Rehorek A. Strategies for continuous on-line high performance liquid chromatography coupled with diode array detection and electrospray tandem mass spectrometry for process monitoring of sulphonated azo dyes and their intermediates in anaerobic–aerobic bioreactors. J Chromatogr A 2005; 1084:119-33. [PMID: 16114245 DOI: 10.1016/j.chroma.2005.03.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
On-line HPLC with diode array detection (DAD) coupled to electrospray tandem mass spectrometry (ESI-MS/MS) is presented as an integrated quality control and process integrated optimisation tool for the continuous monitoring of sulphonated azo dyes (SADs) and their intermediates in anaerobic and aerobic bioprocesses. Ion-pair RP-HPLC is found out to be more suitable for simultaneous monitoring of aromatic amines (AAs), sulphonated aromatic amines (SAAs) and sulphonated azo dyes in comparison to RP-HPLC with polar embedded phases. Monitoring of the anaerobic degradation of the diazo Reactive Black 5 displays the dependency of a two stage azo group reduction mechanism on the redox potential of the bioreactor. An autoxidation sensitive intermediate released from the anaerobic reduction is characterised by ESI-MS/MS for the first time. The functionality of the method is demonstrated by the control and evaluation of selective adaptation of bacteria to certain pollutants and the identification of unknown intermediates causing re-gaining colour released from azo dye treatment.
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Affiliation(s)
- Alexander Plum
- University of Applied Sciences Cologne, Faculty of Process Engineering, Energy and Mechanical Systems, Institute of Chemical Engineering and Plant Design, Betzdorfer Str 2, D-50679 Cologne, Germany
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17
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Real-time monitoring of a pharmaceutical process reaction using a membrane interface combined with atmospheric pressure chemical ionisation mass spectrometry. Anal Chim Acta 2005. [DOI: 10.1016/j.aca.2005.03.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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18
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Affiliation(s)
- Jerome Workman
- Thermo Electron Corporation, 5225 Verona Road, Madison, Wisconsin 53711-4495, USA
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19
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Beyers CP, Boelens HFM, Klumperman L, Westerhuis JA. In-line reaction monitoring of a methyl methacrylate and N, N-dimethylacrylamide copolymerization reaction using near-infrared spectroscopy. APPLIED SPECTROSCOPY 2004; 58:863-869. [PMID: 15282054 DOI: 10.1366/0003702041389346] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Fast and accurate monitoring of monomer concentration during copolymerization reactions is of much interest. It is known that near-infrared spectroscopy (NIRS) can be used to monitor polymerization reactions. Here, a free radical solution copolymerization reaction between methyl methacrylate and N,N-dimethylacrylamide is considered. NIR spectra were measured in-line with a transflectance probe. The spectra of both involved monomers are very similar, making monitoring with NIRS challenging. It is shown that the NIRS calibration can be set up with only a few (5) off-line measured mixtures. Several validation methods for such a NIRS calibration model are discussed and tested. NIRS is used to follow conversion of the two monomers in a copolymerization reaction on-line.
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Affiliation(s)
- C P Beyers
- Polymer Research Division, BASF-AG, D-67056 Ludwigshafen, Germany
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Thurston TJ, Brereton RG, Foord DJ, Escott RE. Principal Components plots for exploratory investigation of reactions using ultraviolet-visible spectroscopy: application to the formation of benzophenone phenylhydrazone. Talanta 2004; 63:757-69. [DOI: 10.1016/j.talanta.2003.12.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2003] [Revised: 11/30/2003] [Accepted: 12/18/2003] [Indexed: 11/16/2022]
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Tabert AM, Griep-Raming J, Guymon AJ, Cooks RG. High-Throughput Miniature Cylindrical Ion Trap Array Mass Spectrometer. Anal Chem 2003; 75:5656-64. [PMID: 14588002 DOI: 10.1021/ac0346858] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A fully multiplexed cylindrical ion trap (CIT) array mass spectrometer with four parallel ion source/mass analyzer/detector channels has been built to allow simultaneous high-throughput analysis of multiple samples. A multielement external chemical ionization/electron ionization source was coupled to a parallel array of CITs each of equal size (internal radius 2.5 mm), and the signal was recorded using an array of four miniature (2-mm inner diameter) electron multipliers. Using external electron ionization, the spectra of four separate samples were recorded simultaneously in real time using a four-channel preamplifier system and a data acquisition program written using LabVIEW software. These experiments mark the first demonstration of externally generated ions being successfully trapped in a miniature CIT mass analyzer. The instrument currently provides mass/charge range of approximately m/z 50-500. Average peak width is m/z 0.3, corresponding to a resolution of 1000 at m/z 300. The four-channel mass spectrometer is housed in a single vacuum manifold and operated with a single set of control electronics. The modular design of this instrument allows scale-up to many more channels of analysis for future applications in the areas of industrial process monitoring and combinatorial analysis and in the fields of proteomics and metabolomics.
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Affiliation(s)
- Amy M Tabert
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
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Affiliation(s)
- Jerome Workman,
- Argose Incorporated, 230 Second Avenue, Waltham, Massachusetts 02451, and Center for Process Analytical Chemistry (CPAC), University of Washington, Seattle, Washington 98195-1700
| | - Mel Koch
- Argose Incorporated, 230 Second Avenue, Waltham, Massachusetts 02451, and Center for Process Analytical Chemistry (CPAC), University of Washington, Seattle, Washington 98195-1700
| | - David J. Veltkamp
- Argose Incorporated, 230 Second Avenue, Waltham, Massachusetts 02451, and Center for Process Analytical Chemistry (CPAC), University of Washington, Seattle, Washington 98195-1700
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Abstract
This Account presents a survey of recent advances in electrochemical sensing technology relevant to green analytical chemistry and examines the potential advantages, limitations, and applications of these monitoring devices. Stricter environmental control and effective process monitoring have created considerable demands for innovative analytical methodologies. New devices and protocols, with negligible waste generation or no hazardous substances, and in situ real-time monitoring capability are particularly needed for addressing the challenges of green analytical chemistry. The coupling of modern electrochemical detection principles with recent advances in molecular recognition, microelectronics, and microfabrication has led to powerful, compact, and "user-friendly" analytical devices. The unique features of such electrochemical monitoring systems make them particularly attractive for addressing environmental and industrial problems and the challenges of green chemistry. These developments allow the instrument to be taken to the sample (rather than the traditional way of bringing the sample to the laboratory) and hence to ensure effective process or pollution control.
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Affiliation(s)
- Joseph Wang
- Department of Chemistry, New Mexico State University, Las Cruces, New Mexico 88003, USA
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Rehorek A, Urbig K, Meurer R, Schäfer C, Plum A, Braun G. Monitoring of azo dye degradation processes in a bioreactor by on-line high-performance liquid chromatography. J Chromatogr A 2002; 949:263-8. [PMID: 11999742 DOI: 10.1016/s0021-9673(01)01427-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A technical solution and development of a method for on-line HPLC monitoring of bioreactor processes in a membrane reactor system are presented. Experiences in system design for the continuous coupling of a bioreactor system with capillary by-pass circuits using membrane flow cells and a dual HPLC system are reported. A continuously working integrated sample purification step by ultrafiltration with the membrane cell coupling is established. Using electrical switching valves and separated pumping and eluent systems, the dual HPLC system allows diode array detection as well as measurement of the refractive index. The application of the on-line HPLC monitoring system is demonstrated by measuring the anaerobic H-acid degradation kinetics. H-acid, 1-amino-8-hydroxynaphthalene-3,6-disulfonic acid, is one of the most important coupling components for a variety of direct, mordant, reactive dyes which remains in the process water and the textile dyeing effluents in high concentration.
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Affiliation(s)
- Astrid Rehorek
- University of Applied Sciences Cologne, Department of Chemical Engineering and Plant Design, Germany.
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