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Spoor E, Rädle M, Repke JU. Raman Spectroscopy of Glass Beads in Ammonium Nitrate Solution and Compensation of Signal Losses. SENSORS (BASEL, SWITZERLAND) 2024; 24:314. [PMID: 38257407 PMCID: PMC10819147 DOI: 10.3390/s24020314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 12/28/2023] [Accepted: 01/04/2024] [Indexed: 01/24/2024]
Abstract
In the present study, the influence of disperse systems on Raman scattering was investigated. How an increasing particle concentration weakens the quantitative signal of the Raman spectrum is shown. Furthermore, the change in the position of the optimal measurement point in the fluid was considered in detail. Additional transmission measurements can be used to derive a simple and robust correction method that allows the actual concentration of the continuous phase to be determined with a standard deviation of 2.6%.
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Affiliation(s)
- Erik Spoor
- Center for Mass Spectrometry and Optical Spectroscopy (CeMOS), Mannheim University of Applied Sciences, Paul-Wittsack-Str. 10, 68163 Mannheim, Germany;
| | - Matthias Rädle
- Center for Mass Spectrometry and Optical Spectroscopy (CeMOS), Mannheim University of Applied Sciences, Paul-Wittsack-Str. 10, 68163 Mannheim, Germany;
| | - Jens-Uwe Repke
- Process Dynamics and Operations Group, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany;
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2
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Wang Z, Yang Z, Song X, Zhang H, Sun B, Zhai J, Yang S, Xie Y, Liang P. Raman spectrum model transfer method based on Cycle-GAN. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 304:123416. [PMID: 37722159 DOI: 10.1016/j.saa.2023.123416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 08/26/2023] [Accepted: 09/13/2023] [Indexed: 09/20/2023]
Abstract
The disparity in hardware quality among various models of Raman spectrometers gives rise to variations in the acquired Raman spectral data, even when the same substance is collected under identical external conditions. Conventionally, models constructed using data obtained from a particular instrument exhibit issues such as limited applicability or poor performance when deployed to different instruments. Currently, numerous model transfer algorithms grounded in chemometrics have been developed, all aiming to establish a mapping relationship capable of transforming spectral data from the source domain to the target domain. With the advancement of deep learning techniques, the utilization of deep learning enables the effective resolution of nonlinear mapping relationships between two spectral vectors. In the field of image translation, the Cycle-Consistent Adversarial Networks, Cycle-GAN, has already achieved mutual transformation between two distinct style images. However, due to images being multidimensional matrix data, unlike one-dimensional spectral data vectors, we have constructed a deep learning network based on Cycle-GAN for vector-to-vector transformation. This network allows the direct conversion of spectral data from the source domain to the target domain, without requiring parameter adjustments or other operations. Compared with traditional chemometric methods, our method is more intelligent and efficient. Finally, the cosine similarity between the source domain data and the transformed target domain data exceeds 99%.
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Affiliation(s)
- Zilong Wang
- College of Optical and Electronic Technology, China Jiliang University, Hangzhou 310018, China
| | - Zhe Yang
- State Key Laboratory of Chemical Safety, SINOPEC Research Institute of Safety Engineering Co., Ltd., Qingdao 266104, China
| | - Xiangning Song
- State Key Laboratory of Chemical Safety, SINOPEC Research Institute of Safety Engineering Co., Ltd., Qingdao 266104, China
| | - Hongzhe Zhang
- State Key Laboratory of Chemical Safety, SINOPEC Research Institute of Safety Engineering Co., Ltd., Qingdao 266104, China
| | - Biao Sun
- School of Electrical and Information Engineering, Tianjin University, No. 92, Weijin Road, Nankai District, Tianjin 300072, China
| | - Jinglei Zhai
- School of Electrical and Information Engineering, Tianjin University, No. 92, Weijin Road, Nankai District, Tianjin 300072, China
| | - Siwei Yang
- College of Optical and Electronic Technology, China Jiliang University, Hangzhou 310018, China
| | - Yuhao Xie
- College of Optical and Electronic Technology, China Jiliang University, Hangzhou 310018, China
| | - Pei Liang
- College of Optical and Electronic Technology, China Jiliang University, Hangzhou 310018, China.
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3
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Hengoju S, Shvydkiv O, Tovar M, Roth M, Rosenbaum MA. Advantages of optical fibers for facile and enhanced detection in droplet microfluidics. Biosens Bioelectron 2022; 200:113910. [PMID: 34974260 DOI: 10.1016/j.bios.2021.113910] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 12/01/2021] [Accepted: 12/20/2021] [Indexed: 11/02/2022]
Abstract
Droplet microfluidics offers a unique opportunity for ultrahigh-throughput experimentation with minimal sample consumption and thus has obtained increasing attention, particularly for biological applications. Detection and measurements of analytes or biomarkers in tiny droplets are essential for proper analysis of biological and chemical assays like single-cell studies, cytometry, nucleic acid detection, protein quantification, environmental monitoring, drug discovery, and point-of-care diagnostics. Current detection setups widely use microscopes as a central device and other free-space optical components. However, microscopic setups are bulky, complicated, not flexible, and expensive. Furthermore, they require precise optical alignments, specialized optical and technical knowledge, and cumbersome maintenance. The establishment of efficient, simple, and cheap detection methods is one of the bottlenecks for adopting microfluidic strategies for diverse bioanalytical applications and widespread laboratory use. Together with great advances in optofluidic components, the integration of optical fibers as a light guiding medium into microfluidic chips has recently revolutionized analytical possibilities. Optical fibers embedded in a microfluidic platform provide a simpler, more flexible, lower-cost, and sensitive setup for the detection of several parameters from biological and chemical samples and enable widespread, hands-on application much beyond thriving point-of-care developments. In this review, we examine recent developments in droplet microfluidic systems using optical fiber as a light guiding medium, primarily focusing on different optical detection methods such as fluorescence, absorbance, light scattering, and Raman scattering and the potential applications in biochemistry and biotechnology that are and will be arising from this.
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Affiliation(s)
- Sundar Hengoju
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, 07745, Jena, Germany; Faculty of Biological Sciences, Friedrich Schiller University, 07743, Jena, Germany
| | - Oksana Shvydkiv
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, 07745, Jena, Germany
| | - Miguel Tovar
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, 07745, Jena, Germany
| | - Martin Roth
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, 07745, Jena, Germany
| | - Miriam A Rosenbaum
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, 07745, Jena, Germany; Faculty of Biological Sciences, Friedrich Schiller University, 07743, Jena, Germany.
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4
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Advances in droplet microfluidics for SERS and Raman analysis. Biosens Bioelectron 2022; 198:113822. [PMID: 34836710 DOI: 10.1016/j.bios.2021.113822] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 11/14/2021] [Accepted: 11/17/2021] [Indexed: 12/14/2022]
Abstract
Raman spectroscopy can realize qualitative and quantitative characterization, and surface-enhanced Raman spectroscopy (SERS) can further enhance its detection sensitivity. In combination with droplet microfluidics, some significant but insurmountable limitations of SERS and Raman spectroscopy can be overcome to some extent, thus improving their detection capability and extending their application. During the past decade, these systems have constantly developed and demonstrated a great potential in more applications, but there is no new review systematically summarizing the droplet microfluidics-based Raman and SERS analysis system since the first related review was published in 2011. Thus, there is a great need for a new review to summarize the advances. In this review, we focus on droplet microfluidics-based Raman and SERS analysis, and summarize two mainstream research directions on this topic up to now. The one is SERS or Raman detection in the moving droplet microreactors, including analysis of molecules, single cells and chemical reaction processes. The other one is SERS active microparticle fabrication via microfluidic droplet templates covering polymer matrix and photonic crystal microparticles. We also comment on the advantages, disadvantage and correlation resolution of droplet microfluidics for SERS or Raman. Finally, we summarize these systems and illustrate our perspectives for future research directions in this field.
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5
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Morin MA, Zhang W(P, Mallik D, Organ MG. Sampling and Analysis in Flow: The Keys to Smarter, More Controllable, and Sustainable Fine‐Chemical Manufacturing. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Mathieu A. Morin
- Department of Chemistry and Biomolecular Sciences Centre for Catalysis Research and Innovation (CCRI) University of Ottawa 10 Marie Curie Ottawa ON K1N 6N5 Canada
- Department of Chemistry Carleton University 203 Steacie Building, 1125 Colonel By Drive Ottawa ON K1S 5B6 Canada
| | - Wenyao (Peter) Zhang
- Department of Chemistry York University 4700 Keele Street Toronto ON M3J 1P3 Canada
| | - Debasis Mallik
- Department of Chemistry and Biomolecular Sciences Centre for Catalysis Research and Innovation (CCRI) University of Ottawa 10 Marie Curie Ottawa ON K1N 6N5 Canada
| | - Michael G. Organ
- Department of Chemistry and Biomolecular Sciences Centre for Catalysis Research and Innovation (CCRI) University of Ottawa 10 Marie Curie Ottawa ON K1N 6N5 Canada
- Department of Chemistry York University 4700 Keele Street Toronto ON M3J 1P3 Canada
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6
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Morin MA, Zhang WP, Mallik D, Organ MG. Sampling and Analysis in Flow: The Keys to Smarter, More Controllable, and Sustainable Fine-Chemical Manufacturing. Angew Chem Int Ed Engl 2021; 60:20606-20626. [PMID: 33811800 DOI: 10.1002/anie.202102009] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/23/2021] [Indexed: 11/08/2022]
Abstract
Process analytical technology (PAT) is a system designed to help chemists better understand and control manufacturing processes. PAT systems operate through the combination of analytical devices, reactor control elements, and mathematical models to ensure the quality of the final product through a quality by design (QbD) approach. The expansion of continuous manufacturing in the pharmaceutical and fine-chemical industry requires the development of PAT tools suitable for continuous operation in the environment of flow reactors. This requires innovative approaches to sampling and analysis from flowing media to maintain the integrity of the reactor content and the analyte of interest. The following Review discusses examples of PAT tools implemented in flow chemistry for the preparation of small organic molecules, and applications of self-optimization tools.
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Affiliation(s)
- Mathieu A Morin
- Department of Chemistry and Biomolecular Sciences, Centre for Catalysis Research and Innovation (CCRI), University of Ottawa, 10 Marie Curie, Ottawa, ON, K1N 6N5, Canada.,Department of Chemistry, Carleton University, 203 Steacie Building, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Wenyao Peter Zhang
- Department of Chemistry, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada
| | - Debasis Mallik
- Department of Chemistry and Biomolecular Sciences, Centre for Catalysis Research and Innovation (CCRI), University of Ottawa, 10 Marie Curie, Ottawa, ON, K1N 6N5, Canada
| | - Michael G Organ
- Department of Chemistry and Biomolecular Sciences, Centre for Catalysis Research and Innovation (CCRI), University of Ottawa, 10 Marie Curie, Ottawa, ON, K1N 6N5, Canada.,Department of Chemistry, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada
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7
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Wang Y, Xue P, Cao M, Yu T, Lane ST, Zhao H. Directed Evolution: Methodologies and Applications. Chem Rev 2021; 121:12384-12444. [PMID: 34297541 DOI: 10.1021/acs.chemrev.1c00260] [Citation(s) in RCA: 184] [Impact Index Per Article: 61.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Directed evolution aims to expedite the natural evolution process of biological molecules and systems in a test tube through iterative rounds of gene diversifications and library screening/selection. It has become one of the most powerful and widespread tools for engineering improved or novel functions in proteins, metabolic pathways, and even whole genomes. This review describes the commonly used gene diversification strategies, screening/selection methods, and recently developed continuous evolution strategies for directed evolution. Moreover, we highlight some representative applications of directed evolution in engineering nucleic acids, proteins, pathways, genetic circuits, viruses, and whole cells. Finally, we discuss the challenges and future perspectives in directed evolution.
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Affiliation(s)
- Yajie Wang
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Pu Xue
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Mingfeng Cao
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Tianhao Yu
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Stephan T Lane
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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8
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Challenges in transfer of gas-liquid reactions from batch to continuous operation: dimensional analysis and simulations for aerobic oxidation. J Flow Chem 2021. [DOI: 10.1007/s41981-021-00176-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
AbstractThe transfer of gas-liquid reactions from conventional batch processes into continuous operation using milli and micro reactors is claimed as an important step towards process intensification. Importantly, this transfer step should be realized in an early phase of process development, already, in order to minimize research efforts towards the undesired operation strategy. The main challenge of this approach, therefore, arises from lack of knowledge in the early stage of process development and the resulting system with high degrees of freedom. This contribution presents an approach to tackle this challenge by means of mathematical modelling and simulation for the aerobic oxidation of 9,10-dihydroanthracene (DHA) catalyzed by polyoxometalates (POMs) being used as example for gas-liquid reactions. The reaction was chosen as it provides sufficient complexity, since it consists of three consecutive oxidation steps of DHA and a parallel catalytic redox-cycle according to a Mars-van-Krevelen mechanism. It also provides the challenge of unknown reaction kinetics, which have been estimated in this contribution. The dimensionless balance equations for reactor modeling are derived and parametrized based on early stage experimental results obtained in batch operation mode. The discrimination between batch and continuous operation was performed by means of characteristic dimensionless numbers using the identical mathematical model for comparability reasons. The model was used to perform sensitivity studies with emphasis on the interplay between mass transfer characteristics and reaction kinetics for both the batch and continuous operation mode. The simulation results show that the performance of both operation modes mainly depend on the oxidation state of the POM catalyst, which is caused by the differences in oxygen availability. Therefore, results obtained in batch operation mode are prone to be masked by mass transfer issues, which affects catalyst and reactor development at the same time and may thus cause maldevelopments. With respect to process development it can thus be concluded that the transfer from batch to continuous operation together with mathematical modeling is important in an early phase, already, in order to detect limitations misleading the development. Finally, even simple models with roughly estimated parameters from preliminary experiments are shown to be sufficient in the early phase and can systematically be improved, in the subsequent phases.
Graphical abstract
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9
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Golparvar A, Boukhayma A, Loayza T, Caizzone A, Enz C, Carrara S. Very Selective Detection of Low Physiopathological Glucose Levels by Spontaneous Raman Spectroscopy with Univariate Data Analysis. BIONANOSCIENCE 2021. [DOI: 10.1007/s12668-021-00867-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractAfter decades of research on non-invasive glucose monitoring, invasive devices based on finger blood sampling are still the predominant reference for diabetic patients for accurately measuring blood glucose levels. Meanwhile, research continues improving point-of-care technology toward the development of painless and more accurate devices. Raman spectroscopy is well-known as a potentially valuable and painless approach for measuring glucose levels. However, previous Raman studies deal with glucose concentrations that are still order of magnitudes away with respect to human tissues’ physiological concentrations, or they propose enhancement methodologies either invasive or much complex to assure sufficient sensitivity in the physiological range. Instead, this study proposes an alternative non-enhanced Raman spectroscopy approach sensitive to glucose concentrations from 1 to 5 mmol/l, which correspond to the lowest physiopathological glucose level in human blood. Our findings suggest a very selective detection of glucose with respect to other typical metabolites, usually interfering with Raman spectroscopy’s glucose detection. We validate the proposed univariate sensing methodology on glucose solutions mixed with lactate and urea, the two most common molecules found in human serum with concentrations similar to glucose and similar features in the Raman spectra. Our findings clearly illustrate that reliable detection of glucose by Raman spectroscopy is feasible by exploiting the shifted peak at 1125 ± 10 cm–1 within physiopathological ranges.
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Klement T, Kockmann N, Schwede C, Röder T. Kinetic Measurement of Acrylic Acid Polymerization at High Concentrations under Nearly Isothermal Conditions in a Pendula Slug Flow Reactor. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.0c04732] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Torsten Klement
- Institute of Chemical Process Engineering, Mannheim University of Applied Sciences, Paul-Wittsack-Strasse 10, Mannheim, 68163, Germany
- Faculty of Biochemical and Chemical Engineering, Laboratory of Equipment Design, TU Dortmund University, Emil-Figge-Strasse 70, Dortmund, 44227, Germany
| | - Norbert Kockmann
- Faculty of Biochemical and Chemical Engineering, Laboratory of Equipment Design, TU Dortmund University, Emil-Figge-Strasse 70, Dortmund, 44227, Germany
| | - Christian Schwede
- BASF SE, RCP/ME-B01, Carl-Bosch-Strasse 38, Ludwigshafen am Rhein, 67056, Germany
| | - Thorsten Röder
- Institute of Chemical Process Engineering, Mannheim University of Applied Sciences, Paul-Wittsack-Strasse 10, Mannheim, 68163, Germany
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11
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“Development and application of analytical detection techniques for droplet-based microfluidics”-A review. Anal Chim Acta 2020; 1113:66-84. [DOI: 10.1016/j.aca.2020.03.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 03/02/2020] [Accepted: 03/05/2020] [Indexed: 01/03/2023]
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12
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Molecule Sensitive Optical Imaging and Monitoring Techniques-A Review of Applications in Micro-Process Engineering. MICROMACHINES 2020; 11:mi11040353. [PMID: 32231076 PMCID: PMC7230497 DOI: 10.3390/mi11040353] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/23/2020] [Accepted: 03/25/2020] [Indexed: 01/21/2023]
Abstract
This paper provides an overview of how molecule-sensitive, spatially-resolved technologies can be applied for monitoring and measuring in microchannels. The principles of elastic light scattering, fluorescence, near-infrared, mid-infrared, and Raman imaging, as well as combination techniques, are briefly presented, and their advantages and disadvantages are explained. With optical methods, images can be acquired both scanning and simultaneously as a complete image. Scanning technologies require more acquisition time, and fast moving processes are not easily observable. On the other hand, molecular selectivity is very high, especially in Raman and mid-infrared (MIR) scanning. For near-infrared (NIR) images, the entire measuring range can be simultaneously recorded with indium gallium arsenide (InGaAs) cameras. However, in this wavelength range, water is the dominant molecule, so it is sometimes necessary to use complex learning algorithms that increase the preparation effort before the actual measurement. These technologies excite molecular vibrations in a variety of ways, making these methods suitable for specific products. Besides measurements of the fluid composition, technologies for particle detection are of additional importance. With scattered light techniques and evaluation according to the Mie theory, particles in the range of 0.2–1 µm can be detected, and fast growth processes can be observed. Local multispectral measurements can also be carried out with fiber optic-coupled systems through small probe heads of approximately 1 mm diameter.
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Yue S, Ye W, Xu Z. SERS monitoring of the Fenton degradation reaction based on microfluidic droplets and alginate microparticles. Analyst 2019; 144:5882-5889. [PMID: 31497808 DOI: 10.1039/c9an01077g] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Surface-enhanced Raman scattering (SERS) spectroscopy as a powerful tool has been used to explore different catalysis degradation reactions, whereas some drawbacks caused by ferric ions still exist in the current SERS monitoring of the Fenton reaction process. In this work, microfluidic droplet- and alginate microparticle-based methods were, respectively, applied to realize SERS monitoring of the Fenton degradation process in a relatively stable environment, which benefited from reduction of the loss of ferrous ions and the aggregation of the SERS substrate. As expected, the spectroscopic evidence at the molecular level directly revealed the degradation mechanism of rhodamine dyes, showing that the chemical bonds between xanthene and carboxybenzene broke continuously during the reaction. Afterward, the degradation mechanism determined by SERS was verified via mass spectrometry detection, which confirmed the validity of the SERS-based method. More broadly, the microfluidic droplet- and microparticle-based methods are potentially applicable for SERS monitoring of more Fenton degradation reactions.
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Affiliation(s)
- Shuai Yue
- Research Center for Analytical Sciences, Northeastern University, Shenyang 110819, P.R. China.
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14
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Comparison of Raman and Mid-Infrared Spectroscopy for Real-Time Monitoring of Yeast Fermentations: A Proof-of-Concept for Multi-Channel Photometric Sensors. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9122472] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Raman and mid-infrared (MIR) spectroscopy are useful tools for the specific detection of molecules, since both methods are based on the excitation of fundamental vibration modes. In this study, Raman and MIR spectroscopy were applied simultaneously during aerobic yeast fermentations of Saccharomyces cerevisiae. Based on the recorded Raman intensities and MIR absorption spectra, respectively, temporal concentration courses of glucose, ethanol, and biomass were determined. The chemometric methods used to evaluate the analyte concentrations were partial least squares (PLS) regression and multiple linear regression (MLR). In view of potential photometric sensors, MLR models based on two (2D) and four (4D) analyte-specific optical channels were developed. All chemometric models were tested to predict glucose concentrations between 0 and 30 g L−1, ethanol concentrations between 0 and 10 g L−1, and biomass concentrations up to 15 g L−1 in real time during diauxic growth. Root-mean-squared errors of prediction (RMSEP) of 0.68 g L−1, 0.48 g L−1, and 0.37 g L−1 for glucose, ethanol, and biomass were achieved using the MIR setup combined with a PLS model. In the case of Raman spectroscopy, the corresponding RMSEP values were 0.92 g L−1, 0.39 g L−1, and 0.29 g L−1. Nevertheless, the simple 4D MLR models could reach the performance of the more complex PLS evaluation. Consequently, the replacement of spectrometer setups by four-channel sensors were discussed. Moreover, the advantages and disadvantages of Raman and MIR setups are demonstrated with regard to process implementation.
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15
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Klement T, Kockmann N, Röder T. Reactor Concept for Contactless Kinetic Measurement in Oscillating Droplets via Raman Spectroscopy. CHEM-ING-TECH 2019. [DOI: 10.1002/cite.201800199] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Torsten Klement
- Mannheim University of Applied SciencesInstitute of Chemical Process Engineering Paul-Wittsack-Straße 10 68163 Mannheim Germany
- TU Dortmund UniversityFaculty of Biochemical and Chemical Engineering, Laboratory of Equipment Design Emil-Figge-Straße 70 44227 Dortmund Germany
| | - Norbert Kockmann
- TU Dortmund UniversityFaculty of Biochemical and Chemical Engineering, Laboratory of Equipment Design Emil-Figge-Straße 70 44227 Dortmund Germany
| | - Thorsten Röder
- Mannheim University of Applied SciencesInstitute of Chemical Process Engineering Paul-Wittsack-Straße 10 68163 Mannheim Germany
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16
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Akwi FM, Watts P. Continuous flow chemistry: where are we now? Recent applications, challenges and limitations. Chem Commun (Camb) 2018; 54:13894-13928. [PMID: 30483683 DOI: 10.1039/c8cc07427e] [Citation(s) in RCA: 128] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A general outlook of the changing face of chemical synthesis is provided in this article through recent applications of continuous flow processing in both industry and academia. The benefits, major challenges and limitations associated with the use of this mode of processing are also given due attention as an attempt to put into perspective the current position of continuous flow processing, either as an alternative or potential combinatory technology for batch processing.
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Affiliation(s)
- Faith M Akwi
- Nelson Mandela University, University Way, Port Elizabeth, 6031, South Africa.
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17
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Non-contact Raman spectroscopy for in-line monitoring of glucose and ethanol during yeast fermentations. Bioprocess Biosyst Eng 2017; 40:1519-1527. [PMID: 28656375 DOI: 10.1007/s00449-017-1808-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 06/20/2017] [Indexed: 02/03/2023]
Abstract
The monitoring of microbiological processes using Raman spectroscopy has gained in importance over the past few years. Commercial Raman spectroscopic equipment consists of a laser, spectrometer, and fiberoptic immersion probe in direct contact with the fermentation medium. To avoid possible sterilization problems and biofilm formation on the probe tip, a large-aperture Raman probe was developed. The design of the probe enables non-contact in-line measurements through glass vessels or inspection glasses of bioreactors and chemical reactors. The practical applicability of the probe was tested during yeast fermentations by monitoring the consumption of substrate glucose and the formation of ethanol as the product. Multiple linear regression models were applied to evaluate the Raman spectra. Reference values were determined by high-performance liquid chromatography. The relative errors of prediction for glucose and ethanol were 5 and 3%, respectively. The presented Raman probe allows simple adaption to a wide range of processes in the chemical, pharmaceutical, and biotechnological industries.
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