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Dabrowska A, Schwaighofer A, Lendl B. Mid-Infrared Dispersion Spectroscopy as a Tool for Monitoring Time-Resolved Chemical Reactions on the Examples of Enzyme Kinetics and Mutarotation of Sugars. APPLIED SPECTROSCOPY 2024:37028241258109. [PMID: 38881172 DOI: 10.1177/00037028241258109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
Ongoing technological advancements in the field of mid-infrared (MIR) spectroscopy continuously yield novel sensing modalities, offering capabilities beyond traditional techniques like Fourier transform infrared spectroscopy (FT-IR). One such advancement is MIR dispersion spectroscopy, utilizing a tunable quantum cascade laser and Mach-Zehnder interferometer for liquid-phase analysis. Our study assesses the performance of a custom MIR dispersion spectrometer at its current development stage, benchmarks its performance against FT-IR, and validates its potential for time-resolved chemical reaction monitoring. Unlike conventional methods of IR spectroscopy measuring molecular absorptions using intensity attenuation, our method detects refractive index changes (phase shifts) down to a level of 6.1 × 10-7 refractive index units (RIU). This results in 1.5 times better sensitivity with a sevenfold increase in analytical path length, yielding heightened robustness for the analysis of liquids compared to FT-IR. As a case study, we monitor the catalytic activity of invertase with sucrose, observing the formation of resultant monosaccharides and their progression toward thermodynamic equilibrium. Anomalous refractive index spectra of reaction mixtures, with substrate concentrations ranging from 2.5 to 25 g/L, are recorded, and analyzed at various temperatures, yielding Michaelis-Menten kinetics findings comparable to the literature. Additionally, the first-time application of two-dimensional correlation spectroscopy on the recorded dynamic dispersion spectra correctly identifies the mutarotation of reaction products (glucose and fructose). The results demonstrate high precision and sensitivity in investigating complex time-dependent chemical reactions via broadband refractive index changes.
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Affiliation(s)
- Alicja Dabrowska
- Research Division of Environmental Analytics, Process Analytics and Sensors, Institute of Chemical Technologies and Analytics, Technische Universität Wien, Vienna, Austria
| | - Andreas Schwaighofer
- Research Division of Environmental Analytics, Process Analytics and Sensors, Institute of Chemical Technologies and Analytics, Technische Universität Wien, Vienna, Austria
- Analytical Development Europe, R&D Pharmaceutical Science, Baxalta Innovations GmbH (part of Takeda), Vienna, Austria
| | - Bernhard Lendl
- Research Division of Environmental Analytics, Process Analytics and Sensors, Institute of Chemical Technologies and Analytics, Technische Universität Wien, Vienna, Austria
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Fomina P, Femenias A, Hlavatsch M, Scheuermann J, Schäfer N, Freitag S, Patel N, Kohler A, Krska R, Koeth J, Mizaikoff B. A Portable Infrared Attenuated Total Reflection Spectrometer for Food Analysis. APPLIED SPECTROSCOPY 2023; 77:1073-1086. [PMID: 37525897 PMCID: PMC10478342 DOI: 10.1177/00037028231190660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 06/11/2023] [Indexed: 08/02/2023]
Abstract
The analytical performance of a compact infrared attenuated total reflection spectrometer using a pyroelectric detector array has been evaluated and compared to a conventional laboratory Fourier transform infrared system for applications in food analysis. Analytical characteristics including sensitivity, repeatability, linearity of the calibration functions, signal-to-noise ratio, and spectral resolution have been derived for both approaches. Representative analytes of relevance in food industries (i.e., organic solvents, fatty acids, and mycotoxins) have been used for the assessment of the performance of the device and to discuss the potential of this technology in food and feed analysis.
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Affiliation(s)
- Polina Fomina
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany
| | - Antoni Femenias
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany
| | - Michael Hlavatsch
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany
| | | | - Nicolas Schäfer
- Nanoplus Nanosystems and Technologies GmbH, Gerbrunn, Germany
| | - Stephan Freitag
- Department of Agrobiotechnology IFA-Tulln, Institute of Bioanalytics and Agro-Metabolomics, University of Natural Resources and Life Sciences Vienna, Tulln, Austria
| | - Nageshvar Patel
- Faculty of Science and Technology, Norwegian University of Life Sciences, Ås, Norway
| | - Achim Kohler
- Faculty of Science and Technology, Norwegian University of Life Sciences, Ås, Norway
| | - Rudolf Krska
- Department of Agrobiotechnology IFA-Tulln, Institute of Bioanalytics and Agro-Metabolomics, University of Natural Resources and Life Sciences Vienna, Tulln, Austria
- School of Biological Science, Institute for Global Food Security, Queen's University Belfast, Belfast, Northern Ireland
| | - Johannes Koeth
- Nanoplus Nanosystems and Technologies GmbH, Gerbrunn, Germany
| | - Boris Mizaikoff
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany
- Hahn-Schickard, Ulm, Germany
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Song W, Fujiwara K, Zhang Z, Morichika I, Ashihara S. Broadband dispersion spectroscopy using interferometric phase modulation under background light suppression. OPTICS LETTERS 2023; 48:4257-4260. [PMID: 37582006 DOI: 10.1364/ol.496288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 07/21/2023] [Indexed: 08/17/2023]
Abstract
This Letter presents a dispersion spectroscopy method that achieves simultaneous detection of molecular vibrational dispersion over a broad spectral range. The method is implemented with an infrared mode-locked laser, a dispersion-compensated Michelson interferometer, and a multichannel detector. Synchronous detection under interferometric phase modulation near the destructive interference condition is employed to achieve a high signal-to-noise ratio. We successfully demonstrate the method by measuring the dispersion of carbon monoxide gas, achieving a noise-equivalent dispersion of 1.3 × 10-8 cm and a corresponding noise-equivalent absorbance of 6.5 × 10-4 with a measurement time of 2.2 s.
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Dabrowska A, Lindner S, Schwaighofer A, Lendl B. Mid-IR dispersion spectroscopy - A new avenue for liquid phase analysis. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 286:122014. [PMID: 36323085 DOI: 10.1016/j.saa.2022.122014] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/14/2022] [Accepted: 10/16/2022] [Indexed: 06/16/2023]
Abstract
Mid-IR dispersion spectroscopy is an attractive, novel approach to liquid phase analysis that extends the possibilities of traditional methods based on the detection of absorption via intensity attenuation. This technique detects inherent refractive index changes (phase shifts) induced by IR light interaction with absorbing matter. In contrast to classic absorption spectroscopy, it provides extended dynamic range, baseline-free detection, constant sensitivity, and inherent immunity to power fluctuation. In this paper, we provide a detailed experimental and theoretical characterization and verification of this method with special focus on broadband liquid sample analysis. For this purpose, we develop a compact benchtop dispersion spectroscopy setup based on an EC-QCL coupled to a Mach-Zehnder interferometer. Phase-locked interferometric detection enables to fully harness the advantages of the technique. By instrument operation in the quadrature point combined with balanced detection, the full immunity towards laser power fluctuations and the environmental noise can be achieved. On the example of ethanol (0.5-50% v/v) dissolved in water, it is experimentally demonstrated that changes of the refractive index function are linearly related to concentration also for strongly absorbing, highly concentrated samples beyond the validity of the Beer-Lambert law. Characterization of the sensitivity and noise behavior indicates that the optimum applicable pathlength for liquid analysis can be extended beyond the ones for absorption spectroscopy. Experimental demonstration of the advantages over classical absorption spectroscopy illuminates the potential of dispersion spectroscopy as upcoming robust and sensitive way of recording IR spectra of liquid samples.
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Affiliation(s)
- Alicja Dabrowska
- Research Division of Environmental Analytics, Process Analytics and Sensors, Institute of Chemical Technologies and Analytics, Technische Universität Wien, Getreidemarkt 9/164-UPA, 1060 Vienna, Austria
| | - Stefan Lindner
- Research Division of Environmental Analytics, Process Analytics and Sensors, Institute of Chemical Technologies and Analytics, Technische Universität Wien, Getreidemarkt 9/164-UPA, 1060 Vienna, Austria
| | - Andreas Schwaighofer
- Research Division of Environmental Analytics, Process Analytics and Sensors, Institute of Chemical Technologies and Analytics, Technische Universität Wien, Getreidemarkt 9/164-UPA, 1060 Vienna, Austria.
| | - Bernhard Lendl
- Research Division of Environmental Analytics, Process Analytics and Sensors, Institute of Chemical Technologies and Analytics, Technische Universität Wien, Getreidemarkt 9/164-UPA, 1060 Vienna, Austria.
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Ricchiuti G, Dabrowska A, Pinto D, Ramer G, Lendl B. Dual-Beam Photothermal Spectroscopy Employing a Mach–Zehnder Interferometer and an External Cavity Quantum Cascade Laser for Detection of Water Traces in Organic Solvents. Anal Chem 2022; 94:16353-16360. [DOI: 10.1021/acs.analchem.2c03303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Giovanna Ricchiuti
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9/164-UPA, Vienna1060, Austria
| | - Alicja Dabrowska
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9/164-UPA, Vienna1060, Austria
| | - Davide Pinto
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9/164-UPA, Vienna1060, Austria
| | - Georg Ramer
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9/164-UPA, Vienna1060, Austria
| | - Bernhard Lendl
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9/164-UPA, Vienna1060, Austria
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Abstract
We suggest a new modality of infrared spectroscopy termed Infrared Refraction Spectroscopy, which is complimentary to absorption spectroscopy. The beauty of this new modality lies not only in its simplicity but also in the fact that it closes an important gap: It allows to quantitatively interpret reflectance spectra by simplest means. First, the refractive index spectrum is calculated from reflectance by neglecting absorption. The change of the refractive index is proportional to concentration, and the spectra with features similar to second derivative absorbance spectra can simply be computed by numerically deriving the refractive index spectra, something which can be easily carried out by standard spectra software packages. The peak values of the derived spectra indicate oscillator positions and are approximately proportional to the concentration in a similar way as absorbance is. In contrast to absorbance spectra, there are no baseline ambiguities for first derivative refractive index spectra, and in refractive index spectra, instead of integrating over a band area, a simple difference of two refractive index values before and after an absorption leads to a quantity that correlates perfectly linearly with concentration in the absence of local field effects.
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Affiliation(s)
- Thomas G Mayerhöfer
- Spectroscopy and Imaging, Leibniz Institute of Photonic Technology (IPHT), Jena, Germany
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University, Jena, Germany
| | - Vladimir Ivanovski
- Faculty of Natural Sciences and Mathematics, Institute of Chemistry, Ss. Cyril and Methodius University in Skopje, Skopje, Macedonia
| | - Jürgen Popp
- Spectroscopy and Imaging, Leibniz Institute of Photonic Technology (IPHT), Jena, Germany
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University, Jena, Germany
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Mayerhöfer TG, Pahlow S, Popp J. Recent technological and scientific developments concerning the use of infrared spectroscopy for point-of-care applications. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 251:119411. [PMID: 33450450 DOI: 10.1016/j.saa.2020.119411] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/27/2020] [Accepted: 12/29/2020] [Indexed: 06/12/2023]
Abstract
In this contribution we review selected point-of-care applications of infrared spectroscopy and the technological innovations they are based on. After a short introduction summarizing the general idea behind point-of-care applications we introduce the reader to important infrared spectroscopy sensing principles on a very basic level. We discuss the role of optical components like quantum cascade lasers, supercontinuum sources, waveguides and how they are potentially going to revolutionize point-of-care applications. First, we focus on the technological solutions of some principal problems like increasing the pathlength in a transmission cell to enhance the sensitivity for solutes in aqueous solutions and discuss indirect methods which circumvent the problem of low transmittance. In the second part we show how the technological progress of the last decades enabled scientific progress leading to selected concrete and outstanding point-of-care solutions and applications based on infrared spectroscopy. These include the detection and quantification of malaria parasitemia, early recognition of Alzheimer's disease long before the onset of clinical symptoms and a non-invasive method for testing the blood glucose content. The selected examples demonstrate and showcase that infrared spectroscopy is on the way to become an indispensable technique for point-of-care applications.
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Affiliation(s)
- Thomas G Mayerhöfer
- Leibniz Institute of Photonic Technology (IPHT), Albert-Einstein-Str. 9, D-07745 Jena, Germany; Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University, Jena, D-07743, Helmholtzweg 4, Germany
| | - Susanne Pahlow
- Leibniz Institute of Photonic Technology (IPHT), Albert-Einstein-Str. 9, D-07745 Jena, Germany; Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University, Jena, D-07743, Helmholtzweg 4, Germany
| | - Jürgen Popp
- Leibniz Institute of Photonic Technology (IPHT), Albert-Einstein-Str. 9, D-07745 Jena, Germany; Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University, Jena, D-07743, Helmholtzweg 4, Germany.
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Dabrowska A, Schwaighofer A, Lindner S, Lendl B. Mid-IR refractive index sensor for detecting proteins employing an external cavity quantum cascade laser-based Mach-Zehnder interferometer. OPTICS EXPRESS 2020; 28:36632-36642. [PMID: 33379753 DOI: 10.1364/oe.403981] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/20/2020] [Indexed: 06/12/2023]
Abstract
Novel laser light sources in the mid-infrared region enable new spectroscopy schemes beyond classical absorption spectroscopy. Herein, we introduce a refractive index sensor based on a Mach-Zehnder interferometer and an external-cavity quantum cascade laser that allows rapid acquisition of high-resolution spectra of liquid-phase samples, sensitive to relative refractive index changes down to 10-7. Dispersion spectra of three model proteins in deuterated solution were recorded at concentrations as low as 0.25 mg mL-1. Comparison with Kramers-Kronig-transformed Fourier transform infrared absorbance spectra revealed high conformance, and obtained figures of merit compare well with conventional high-end FTIR spectroscopy. Finally, we performed partial least squares-based multivariate analysis of a complex ternary protein mixture to showcase the potential of dispersion spectroscopy utilizing the developed sensor to tackle complex analytical problems. The results indicate that laser-based dispersion sensing can be successfully used for qualitative and quantitative analysis of proteins.
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