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Fekete G, Sebők A, Klátyik S, Varga ZI, Grósz J, Czinkota I, Székács A, Aleksza L. Comparative Analysis of Laboratory-Based and Spectroscopic Methods Used to Estimate the Algal Density of Chlorella vulgaris. Microorganisms 2024; 12:1050. [PMID: 38930433 PMCID: PMC11205756 DOI: 10.3390/microorganisms12061050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 05/17/2024] [Accepted: 05/18/2024] [Indexed: 06/28/2024] Open
Abstract
Chlorella vulgaris is of great importance in numerous exploratory or industrial applications (e.g., medicals, food, and feed additives). Rapid quantification of algal biomass is crucial in photobioreactors for the optimization of nutrient management and the estimation of production. The main goal of this study is to provide a simple, rapid, and not-resource-intensive estimation method for determining the algal density of C. vulgaris according to the measured parameters using UV-Vis spectrophotometry. Comparative assessment measurements were conducted with seven different methods (e.g., filtration, evaporation, chlorophyll a extraction, and detection of optical density and fluorescence) to determine algal biomass. By analyzing the entire spectra of diluted algae samples, optimal wavelengths were determined through a stepwise series of linear regression analyses by a novel correlation scanning method, facilitating accurate parameter estimation. Nonlinear formulas for spectrometry-based estimation processes were derived for each parameter. As a result, a general formula for biomass concentration estimation was developed, with recommendations for suitable measuring devices based on algae concentration levels. New values for magnesium content and the average single-cell weight of C. vulgaris were established, in addition to the development of a rapid, semiautomated cell counting method, improving efficiency and accuracy in algae quantification for cultivation and biotechnology applications.
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Affiliation(s)
- György Fekete
- Institute of Environmental Sciences, Hungarian University of Agriculture and Life Sciences, Páter Károly u. 1, H-2100 Gödöllő, Hungary; (G.F.); (A.S.); (S.K.); (Z.I.V.); (J.G.); (I.C.); (L.A.)
| | - András Sebők
- Institute of Environmental Sciences, Hungarian University of Agriculture and Life Sciences, Páter Károly u. 1, H-2100 Gödöllő, Hungary; (G.F.); (A.S.); (S.K.); (Z.I.V.); (J.G.); (I.C.); (L.A.)
| | - Szandra Klátyik
- Institute of Environmental Sciences, Hungarian University of Agriculture and Life Sciences, Páter Károly u. 1, H-2100 Gödöllő, Hungary; (G.F.); (A.S.); (S.K.); (Z.I.V.); (J.G.); (I.C.); (L.A.)
| | - Zsolt István Varga
- Institute of Environmental Sciences, Hungarian University of Agriculture and Life Sciences, Páter Károly u. 1, H-2100 Gödöllő, Hungary; (G.F.); (A.S.); (S.K.); (Z.I.V.); (J.G.); (I.C.); (L.A.)
| | - János Grósz
- Institute of Environmental Sciences, Hungarian University of Agriculture and Life Sciences, Páter Károly u. 1, H-2100 Gödöllő, Hungary; (G.F.); (A.S.); (S.K.); (Z.I.V.); (J.G.); (I.C.); (L.A.)
| | - Imre Czinkota
- Institute of Environmental Sciences, Hungarian University of Agriculture and Life Sciences, Páter Károly u. 1, H-2100 Gödöllő, Hungary; (G.F.); (A.S.); (S.K.); (Z.I.V.); (J.G.); (I.C.); (L.A.)
| | - András Székács
- Institute of Environmental Sciences, Hungarian University of Agriculture and Life Sciences, Páter Károly u. 1, H-2100 Gödöllő, Hungary; (G.F.); (A.S.); (S.K.); (Z.I.V.); (J.G.); (I.C.); (L.A.)
| | - László Aleksza
- Institute of Environmental Sciences, Hungarian University of Agriculture and Life Sciences, Páter Károly u. 1, H-2100 Gödöllő, Hungary; (G.F.); (A.S.); (S.K.); (Z.I.V.); (J.G.); (I.C.); (L.A.)
- Profikomp Environmental Technologies Inc., Kühne Ede u. 7, H-2100 Gödöllő, Hungary
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2
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Fung S, Contreras RP, Fung AG, Gibson P, LeVasseur MK, McCartney MM, Koch DT, Chakraborty P, Chew BS, Rajapakse MY, Chevy DA, Hicks TL, Davis CE. Portable chemical detection platform for on-site monitoring of odorant levels in natural gas. J Chromatogr A 2023; 1705:464151. [PMID: 37419015 PMCID: PMC11014743 DOI: 10.1016/j.chroma.2023.464151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/09/2023] [Accepted: 06/11/2023] [Indexed: 07/09/2023]
Abstract
The adequate odorization of natural gas is critical to identify gas leaks and to reduce accidents. To ensure odorization, natural gas utility companies collect samples to be processed at core facilities or a trained human technician smells a diluted natural gas sample. In this work, we report a detection platform that addresses the lack of mobile solutions capable of providing quantitative analysis of mercaptans, a class of compounds used to odorize natural gas. Detailed description of the platform hardware and software components is provided. Designed to be portable, the platform hardware facilitates extraction of mercaptans from natural gas, separation of individual mercaptan species, and quantification of odorant concentration, with results reported at point-of-sampling. The software was developed to accommodate skilled users as well as minimally trained operators. Detection and quantification of six commonly used mercaptan compounds (ethyl mercaptan, dimethyl sulfide, n-propylmercaptan, isopropyl mercaptan, tert‑butyl mercaptan, and tetrahydrothiophene) at typical odorizing concentrations of 0.1-5 ppm was performed using the device. We demonstrate the potential of this technology to ensure natural gas odorizing concentrations throughout distribution systems.
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Affiliation(s)
- Stephanie Fung
- Department of Mechanical and Aerospace Engineering, University of California Davis, Davis, CA, USA; UC Davis Lung Center, One Shields Avenue, Davis, CA 95616, USA
| | - Raquel Pimentel Contreras
- Department of Mechanical and Aerospace Engineering, University of California Davis, Davis, CA, USA; UC Davis Lung Center, One Shields Avenue, Davis, CA 95616, USA
| | - Alexander G Fung
- Department of Mechanical and Aerospace Engineering, University of California Davis, Davis, CA, USA; UC Davis Lung Center, One Shields Avenue, Davis, CA 95616, USA
| | - Patrick Gibson
- Department of Mechanical and Aerospace Engineering, University of California Davis, Davis, CA, USA; UC Davis Lung Center, One Shields Avenue, Davis, CA 95616, USA
| | - Michael K LeVasseur
- Department of Mechanical and Aerospace Engineering, University of California Davis, Davis, CA, USA; UC Davis Lung Center, One Shields Avenue, Davis, CA 95616, USA
| | - Mitchell M McCartney
- Department of Mechanical and Aerospace Engineering, University of California Davis, Davis, CA, USA; UC Davis Lung Center, One Shields Avenue, Davis, CA 95616, USA.; VA Northern California Health Care System, 10535 Hospital Way, Mather, CA 95655, USA
| | - Dylan T Koch
- UC Davis Lung Center, One Shields Avenue, Davis, CA 95616, USA.; Department of Electrical Engineering, University of California Davis, Davis, CA, USA
| | - Pranay Chakraborty
- Department of Mechanical and Aerospace Engineering, University of California Davis, Davis, CA, USA; UC Davis Lung Center, One Shields Avenue, Davis, CA 95616, USA
| | - Bradley S Chew
- Department of Mechanical and Aerospace Engineering, University of California Davis, Davis, CA, USA; UC Davis Lung Center, One Shields Avenue, Davis, CA 95616, USA
| | - Maneeshin Y Rajapakse
- Department of Mechanical and Aerospace Engineering, University of California Davis, Davis, CA, USA; UC Davis Lung Center, One Shields Avenue, Davis, CA 95616, USA
| | - Daniel A Chevy
- UC Davis Lung Center, One Shields Avenue, Davis, CA 95616, USA.; Department of Electrical Engineering, University of California Davis, Davis, CA, USA
| | - Tristan L Hicks
- Department of Mechanical and Aerospace Engineering, University of California Davis, Davis, CA, USA; UC Davis Lung Center, One Shields Avenue, Davis, CA 95616, USA
| | - Cristina E Davis
- Department of Mechanical and Aerospace Engineering, University of California Davis, Davis, CA, USA; UC Davis Lung Center, One Shields Avenue, Davis, CA 95616, USA.; VA Northern California Health Care System, 10535 Hospital Way, Mather, CA 95655, USA.
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3
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Li C, Chen P, Khan IM, Wang Z, Zhang Y, Ma X. Fluorescence-Raman dual-mode quantitative detection and imaging of small-molecule thiols in cell apoptosis with DNA-modified gold nanoflowers. J Mater Chem B 2022; 10:571-581. [PMID: 34994374 DOI: 10.1039/d1tb02437j] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The monitoring of small-molecule thiols (especially glutathione) has attracted widespread attention due to their involvement in numerous physiological processes in living organisms and cells. In this work, a dual-mode nanosensor was designed to detect small-molecule thiols, which is based on the "on-off" switch of fluorescence resonance energy transfer (FRET) and surface-enhanced Raman scattering (SERS). Briefly, DNA was modified by Cy5 (signal probe) and disulfide bonds (recognition element). Gold nanoflowers (AuNFs) were used as the fluorescence-quenching and SERS-enhancing substrate. However, small-molecule thiols can cleave disulfide bonds and release short Cy5-labeled chains, causing the recovery of the fluorescence signal and a decrease of the SERS signal. The nanosensor showed a sensitive response to small-molecule thiols represented by GSH, with a linear range of 0.01-3 mM and a detection limit of 913 nM. In addition, it competed with other related biological interferences and presented good stability and better selectivity towards small-molecule thiols. Most importantly, the developed nanosensor had been successfully applied to in situ imaging and quantitative monitoring of the concentration of small-molecule thiols which changed during T-2 toxin-induced apoptosis in HeLa cells. Meanwhile, nanosensors are also versatile with their potential applications and can be easily extended to the detection and imaging of other human cell lines. The proposed method combines the dual advantages of fluorescence and SERS, which has broad prospects for in situ studies of physiological processes involving small-molecule thiols in biological systems.
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Affiliation(s)
- Chenbiao Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China. .,School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China.,Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi 214122, China
| | - Peifang Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China. .,School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China.,Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi 214122, China
| | - Imran Mahmood Khan
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China. .,School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China.,Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi 214122, China
| | - Zhouping Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China. .,School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China.,Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi 214122, China.,Key Laboratory of Meat Processing of Sichuan, Chengdu University, Chengdu 610106, China
| | - Yin Zhang
- Key Laboratory of Meat Processing of Sichuan, Chengdu University, Chengdu 610106, China
| | - Xiaoyuan Ma
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China. .,School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China.,Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi 214122, China
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Kukor AJ, Depner N, Cai I, Tucker JL, Culhane JC, Hein JE. Enantioselective synthesis of (−)-tetrabenazine via continuous crystallization-induced diastereomer transformation. Chem Sci 2022; 13:10765-10772. [PMID: 36320713 PMCID: PMC9491067 DOI: 10.1039/d2sc01825j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 08/23/2022] [Indexed: 11/24/2022] Open
Abstract
A multi-well continuous CIDT approach with inline racemization of the solution phase is presented. Using two in-house built PATs and a flow reactor, we were able to successfully crystallize an enantiopure salt of TBZ, the active metabolite of the tardive dyskinesia drug valbenazine. Despite discovering an undesired racemic solid phase, inline racemization combined with careful control of crystallization conditions allowed for multigram quantities of enantiopure material to be harvested using our setup. Critically, this control was made possible by the use of PATs to observe and quantify the composition of both the solid and solution phases. A novel enantioselective route to tetrabenazine has been developed using continuous CIDT in a multiwell crystallization/racemization device outfitted with real-time HPLC to visualize and control the dynamic process.![]()
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Affiliation(s)
- Andrew J. Kukor
- Department of Chemistry, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Noah Depner
- Department of Chemistry, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Isabelle Cai
- Department of Chemistry, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - John L. Tucker
- Neurocrine Biosciences, San Diego, California, 92130, USA
| | | | - Jason E. Hein
- Department of Chemistry, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
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5
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Barreto D, Kokoric V, da Silveira Petruci JF, Mizaikoff B. From Light Pipes to Substrate-Integrated Hollow Waveguides for Gas Sensing: A Review. ACS MEASUREMENT SCIENCE AU 2021; 1:97-109. [PMID: 36785552 PMCID: PMC9836072 DOI: 10.1021/acsmeasuresciau.1c00029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Absorption-based spectroscopy in the mid-infrared (MIR) spectral range (i.e., 2.5-25 μm) is an excellent choice for directly sensing trace gas analytes providing discriminatory molecular information due to inherently specific fundamental vibrational, rovibrational, and rotational transitions. Complimentarily, the miniaturization of optical components has aided the utility of optical sensing techniques in a wide variety of application scenarios that demand compact, portable, easy-to-use, and robust analytical platforms yet providing suitable accuracy, sensitivity, and selectivity. While MIR sensing technologies have clearly benefitted from the development of advanced on-chip light sources such as quantum cascade and interband cascade lasers and equally small MIR detectors, less attention has been paid to the development of modular/tailored waveguide technologies reproducibly and reliably interfacing photons with sample molecules in a compact format. In this context, the first generation of a new type of hollow waveguides gas cells-the so-called substrate-integrated hollow waveguides (iHWG)-with unprecedented compact dimensions published by the research team of Mizaikoff and collaborators has led to a paradigm change in optical transducer technology for gas sensors. Features of iHWGs included an adaptable (i.e., designable) well-defined optical path length via the integration of meandered hollow waveguide structures at virtually any desired dimension and geometry into an otherwise planar substrate, a high degree of robustness, compactness, and cost-effectiveness in fabrication. Moreover, only a few hundred microliters of gas samples are required for analysis, resulting in short sample transient times facilitating a real-time monitoring of gaseous species in virtually any concentration range. In this review, we give an overview of recent advancements and achievements since their introduction eight years ago, focusing on the development of iHWG-based mid-infrared sensor technologies. Highlighted applications ranging from clinical diagnostics to environmental and industrial monitoring scenarios will be contrasted by future trends, challenges, and opportunities for the development of next-generation portable optical gas-sensing platforms that take advantage of a modular and tailorable device design.
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Affiliation(s)
- Diandra
Nunes Barreto
- Institute
of Chemistry, Federal University of Uberlândia, Uberlândia 38400-902, MG, Brazil
| | - Vjekoslav Kokoric
- Institute
for Microanalysis Systems, Hahn-Schickard, Ulm 89077, Germany
| | | | - Boris Mizaikoff
- Institute
for Microanalysis Systems, Hahn-Schickard, Ulm 89077, Germany
- Institute
of Analytical and Bioanalytical Chemistry, Ulm University, Ulm 89081, Germany
- e-mail:
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7
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Kukor AJ, Guy MA, Hawkins JM, Hein JE. A robust new tool for online solution-phase sampling of crystallizations. REACT CHEM ENG 2021. [DOI: 10.1039/d1re00284h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Dynamically flushed filter allows for sampling of crystallizations.
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Affiliation(s)
- Andrew J. Kukor
- Department of Chemistry, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Mason A. Guy
- Department of Chemistry, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Joel M. Hawkins
- Pfizer Global Research & Development, Groton, Connecticut, 06371, USA
| | - Jason E. Hein
- Department of Chemistry, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
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8
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Guo R, Zhang X, He AQ, Yu ZQ, Ling XF, Xu YZ, Noda I, Ozaki Y, Wu JG. Sample–Sample Correlation Asynchronous Spectroscopic Method Coupled with Multivariate Curve Resolution-Alternating Least Squares To Analyze Challenging Bilinear Data. Anal Chem 2019; 92:1477-1484. [DOI: 10.1021/acs.analchem.9b04730] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Ran Guo
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, P.R. China
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P.R. China
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P.R. China
| | - Xin Zhang
- Department of Chemistry, Capital Normal University, Beijing 100048, P.R. China
| | - An-Qi He
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P.R. China
| | - Zhen-Qiang Yu
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, P.R. China
| | - Xiao-Feng Ling
- The Third School of Clinical Medicine of Peking University, Beijing 100083, P.R. China
| | - Yi-Zhuang Xu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P.R. China
| | - Isao Noda
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P.R. China
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Yukihiro Ozaki
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P.R. China
- Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan
| | - Jin-Guang Wu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P.R. China
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9
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Hagemann LT, Ehrle S, Mizaikoff B. Optimizing the Analytical Performance of Substrate-Integrated Hollow Waveguides: Experiment and Simulation. APPLIED SPECTROSCOPY 2019; 73:1451-1460. [PMID: 31397586 DOI: 10.1177/0003702819867342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The goal of this technical note was to compare experimentally and via simulation of eight substrate-integrated hollow waveguide (iHWG) designs, and to predict promising future iHWG structures in lieu of experiments. The iHWGs differed in their geometry (i.e., inlet funnel cross-section and inner channel cross-section), as well as in their material properties (i.e., type of metal, polish of inner channel). Experimentally, calibration functions of isobutane as a model analyte were determined, and the analytical figures of merit, i.e., signal-to-noise ratio, limit of detection, were evaluated for each iHWG. Evaluation of the amount of radiation incident at the real-world and simulated detector revealed that experiment and simulation were in excellent agreement. While material and quality of the inner channel wall did not have a significant influence on the performance, the iHWG geometry profoundly affected the performance in terms of light throughput: Increasing the inlet funnel dimensions and the inner channel cross-section benefits light throughout, and thus, the analytical signal. Based on these results, simulations of not yet fabricated iHWGs were performed and promising new iHWG structures were suggested.
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Affiliation(s)
| | - Sonja Ehrle
- Institute of Analytical and Bioanalytical Chemistry, Ulm, Germany
| | - Boris Mizaikoff
- Institute of Analytical and Bioanalytical Chemistry, Ulm, Germany
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Hybrid Analytical Platform Based on Field-Asymmetric Ion Mobility Spectrometry, Infrared Sensing, and Luminescence-Based Oxygen Sensing for Exhaled Breath Analysis. SENSORS 2019; 19:s19122653. [PMID: 31212768 PMCID: PMC6630267 DOI: 10.3390/s19122653] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 06/07/2019] [Accepted: 06/09/2019] [Indexed: 12/19/2022]
Abstract
The reliable online analysis of volatile compounds in exhaled breath remains a challenge, as a plethora of molecules occur in different concentration ranges (i.e., ppt to %) and need to be detected against an extremely complex background matrix. Although this complexity is commonly addressed by hyphenating a specific analytical technique with appropriate preconcentration and/or preseparation strategies prior to detection, we herein propose the combination of three different detector types based on truly orthogonal measurement principles as an alternative solution: Field-asymmetric ion mobility spectrometry (FAIMS), Fourier-transform infrared (FTIR) spectroscopy-based sensors utilizing substrate-integrated hollow waveguides (iHWG), and luminescence sensing (LS). By carefully aligning the experimental needs and measurement protocols of all three methods, they were successfully integrated into a single compact analytical platform suitable for online measurements. The analytical performance of this prototype system was tested via artificial breath samples containing nitrogen (N2), oxygen (O2), carbon dioxide (CO2), and acetone as a model volatile organic compound (VOC) commonly present in breath. All three target analytes could be detected within their respectively breath-relevant concentration range, i.e., CO2 and O2 at 3-5 % and at ~19.6 %, respectively, while acetone could be detected with LOQs as low as 165-405 ppt. Orthogonality of the three methods operating in concert was clearly proven, which is essential to cover a possibly wide range of detectable analytes. Finally, the remaining challenges toward the implementation of the developed hybrid FAIMS-FTIR-LS system for exhaled breath analysis for metabolic studies in small animal intensive care units are discussed.
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11
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Chen K, Zhao Z, Zhang X, Zhang X, Zhu X, Shi Y. Characterization of Gas Absorption Modules Based on Flexible Mid-Infrared Hollow Waveguides. SENSORS 2019; 19:s19071698. [PMID: 30974732 PMCID: PMC6480174 DOI: 10.3390/s19071698] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 04/04/2019] [Accepted: 04/04/2019] [Indexed: 11/16/2022]
Abstract
A new gas absorption module, the substrate-embedded hollow waveguide (eHWG) model, is proposed. It consists of a substrate with a curved channel and a hollow waveguide. The hollow waveguide is curved into the channel and works as a gas absorption cell as well as a transmission medium for mid-infrared light. Owing to the low loss property of the hollow waveguide, the signal-to-noise ratio (SNR) was improved for the sensing system. A polycarbonate (PC) base tube was used to obtain flexibility in the fabrication of the hollow waveguide. A silver (Ag) layer and a silver iodide (AgI) layer were inner-coated to ensure a low loss property at the fingerprint wavelength of methane gas. A sensing system was established using a Fourier transform infrared spectrometer (FTIR), an external detector, and an eHWG. Experimental investigations were carried on the sensing performance of eHWGs with various channel shapes. Comparison studies were made on eHWGs embedded with Ag-coated or Ag- and AgI-coated hollow waveguides. The Ag- and AgI-coated hollow waveguides with inner diameters of 0.7, 1.4, and 2.0 mm were used in the eHWGs. The large bore waveguide had low loss but high bending additional loss. The large bore waveguide had a low detection limit due to high coupling efficiency with the light source. A limit of detection (LOD) as low as 2.7 ppm was attained for the system using the eHWG with the long and large bore waveguide.
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Affiliation(s)
- Kewang Chen
- Key Laboratory for Information Science of Electromagnetic Waves (MoE), Fudan University, Shanghai 200433, China.
| | - Zeqiao Zhao
- Key Laboratory for Information Science of Electromagnetic Waves (MoE), Fudan University, Shanghai 200433, China.
| | - Xuewen Zhang
- Key Laboratory for Information Science of Electromagnetic Waves (MoE), Fudan University, Shanghai 200433, China.
| | - Xian Zhang
- Key Laboratory for Information Science of Electromagnetic Waves (MoE), Fudan University, Shanghai 200433, China.
| | - Xiaosong Zhu
- Key Laboratory for Information Science of Electromagnetic Waves (MoE), Fudan University, Shanghai 200433, China.
| | - Yiwei Shi
- Key Laboratory for Information Science of Electromagnetic Waves (MoE), Fudan University, Shanghai 200433, China.
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