Norwegian University of Science and Technology (2020)
Mid-Infrared Tuneable Laser Spectroscopy for Glucose Sensing
Authors: Jernelv, Ine Larsen; Milenko, Karolina Barbara; Fuglerud, Silje Skeide; Hjelme, Dag Roar; Ellingsen, Reinold; Aksnes, Astrid
This thesis presents contributions on QCL-based spectroscopy and chemometric methods. Additional investigation is done into signal-enhanced attenuated total reflection (ATR) spectroscopy, and a comprehensive study of multivariate analysis with convolutional neural networks and other chemometric methods is also included. The presented results show that fibre-coupled setups in transmission and ATR configurations are both suitable for measurements of glucose in peritoneal fluid. This system has a high potential for further testing in animal trials, and may be realized as a CGM device for humans.
Potential-Dependent Layering in the Electrochemical Double Layer of Water-in-Salt Electrolytes
Authors: Ruixian Zhang, Mengwei Han, Kim Ta, Kenneth E. Madsen, Xinyi Chen, Xueyong Zhang, Rosa M. Espinosa-Marzal, and Andrew A. Gewirth
Water-in-salt electrolytes (WiSE), are especially relevant to batteries due to their percolating nanodomains in bulk. However, these types of electrolytes are still poorly understood and characterized at interfaces. This article addresses that gap, characterizing LiTFSI electrolytes and their formation of a double layer, on a charged electrode surface. For a better understanding of WiSE, different techniques were used, including infrared spectroscopy with IRUBIS silicon ATR crystals.
Signal enhancement in microstructured silicon attenuated total reflection elements with quantum cascade laser-based spectroscopy
Authors: Ine L. Jernelv, Jens Høvik, Dag Roar Hjelme, and Astrid Aksnes
In this study, the performance of basic and signal-enhanced Si IREs has been compared for measurements in a spectroscopy setup with a fibre-coupled tuneable QCL source. These IREs had V-shaped microgrooves etched on the underside for more efficient in-coupling of light, while the signal enhanced IREs also had micropillars on the top surface. The results are also contrasted with measurements done in a standard ATR-FTIR spectrometer, using an Alpha II spectrometer with a single-reflection diamond ATR crystal. Various concentrations of glucose (0-5000 mg/dl) in aqueous solutions were used to characterise the system performance.
Spectroelectrochemistry, the future of visualizing electrode processes by hyphenating electrochemistry with spectroscopic techniques
Authors: JJA Lozeman, P Führer, W Olthuis, M Odijk
Spectroelectrochemistry (SEC) allows you to obtain more data than by using electrochemistry and spectroscopy independently. This review focusses on four techniques, the authors claim to have the most potential for the future, namely: infrared SEC (IR-SEC), Raman SEC, NMR-SEC and EC-MS.
The Jackfish SEC, a three-electrode electrochemical ATR cell from Pike Technologies, is named as a novel technology combining the fields of IR and SEC. The authors also point out that using the disposable IRUBIS Specialized 1 ATR Crystal for ATR-SEIRAS, IR-SEC becomes suitable for a broader audience.
European Journal of Clinical Microbiology & Infectious Diseases (2019)
Fourier transform infrared spectroscopy: unlocking fundamentals and prospects for bacterial strain typing
Authors: A Novais, AR Freitas, C Rodrigues, L Peixe
This publication highlights the importance of bacterial typing to identify bacterial strains in clinical, industrial, or environmental microbiology. It shows how FT-IR can be used as a method that combines a high reliability and accuracy with a rapid, low-cost, and user-friendly performance and how new developments, such as the disposable IRUBIS Universal ATR Crystal, can contribute to this.
It is demonstrated how FT-IR-based bacterial typing might not only useful for strain typing but could also to help understanding the diversity, evolution, and host adaptation factors of important bacterial pathogens or subpopulations.
Micromachined multigroove silicon ATR FT-IR internal reflection elements for chemical imaging of microfluidic devices
Authors: TA Morhart, ST Read, G Wells, M Jacobs, SM Rosendahl, S Achenbach, IJ Burgess
This research demonstrates proof of concept chemical imaging with μ-groove IREs through the successful mapping of isotope exchange between two co-laminar flows of water and heavy water in a single microfluidic channel. A prospective on how imaging quality with near diffraction limited spatial resolution could be achieved is also provided.
Analytical performance of μ-groove silicon attenuated total reflection waveguides
Authors: J Haas, A Müller, L Sykora,B Mizaikoff
The analytical performance of micromachined μ-groove silicon ATR elements has been evaluated in a comparison of FTIR and QCL spectroscopy operating at MIR wavelengths. μ-Groove silicon ATR elements are highly efficient micromachined waveguides fabricated at a wafer scale at such low cost that they may be considered a consumable for single-time-use, e.g., in medical application scenarios. Herein, exemplary analytes haven been used for reliably evaluating their analytical performance (i.e., acetate and carbonate) in terms of sensitivity, noise level, and achievable limits of detection in a comparison of broadband vs. narrowband infrared spectroscopy.
Hybrid Gold–Conductive Metal Oxide Films for Attenuated Total Reflectance Surface Enhanced Infrared Absorption Spectroscopy
Authors: I R Andvaag, T A Morhart, O J R Clarke, I J Burgess
The use of conductive metal oxide (CMO) films as supporting layers for ATR-SEIRAS is treated theoretically and experimentally. The greater mid-infrared transparency of thin layers of indium zinc oxide (IZO), as compared to metals, is verified through IR reflectivity measurements and the Drude model. IZO layers sputtered on our Specialized 1 ATR Crystals are found to have a thin surface layer with slightly different plasma frequency and electronic scattering time compared to the bulk material.
Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectromicroscopy Using Synchrotron Radiation and Micromachined Silicon Wafers for Microfluidic Applications
Authors: T Morhart, S Read, G Wells, M Jacobs, S Rosendahl, S Achenbach, I J Burgess
This paper describes a custom-designed optical configuration for ATR FT-IR spectroscopy and imaging applications in microfluidic devices, compatible with the IRUBIS ATR Crystals. Results show that our crystals are highly compatible with standard photolithographic techniques. ATR FT-IR mapping as a function of sample position across the channel illustrates the potential application of this approach for rapid prototyping of microfluidic devices.
Parasites under the Spotlight: Applications of Vibrational Spectroscopy to Malaria Research
Authors: D Perez-Guaita, K M Marzec, A Hudson, C Evans, T Chernenko, C Matthäus, M Miljkovic, M Diem, P Heraud, J S Richards, D Andrew, D A Anderson, C Doerig, J Garcia-Bustos, D McNaughton, B R Wood
Infrared spectroscopy can be used as an anlytical method for biofluids. One application is the diagnosis of malaria.
The analysis of biofluids with IR is always a question of hygiene. Using our Universal ATR Crystals as a cost-effective and disposable alternative to diamonds enables many new applications.
Electrochemical ATR-SEIRAS Using Low-Cost, Micromachined Si Wafers
Authors: T A Morhart, B Unni, M J Lardner, I J Burgess
Researchers from Canada used our Universal ATR Crystals for electrochemical ATR Surface Enhanced Infrared Absorption Spectroscopy. If you are interested in this application, we now also offer the Specialized 1, an ATR Crystals optimized for applications like SEIRAS.
Non-invasive MIR Spectroscopy for Glucose Control and Monitoring during Fed Batch Phase
H. Marienberg, München/DE, A. Müller, München/DE, V. Mozin, München/DE,
L. Sykora, München/DE, A. Geißler, München/DE, A. Roth, München/DE
Here we present our mid-infrared (MIR) spectroscopy system “Monipa”, which can keep the glucose concentration constant in the fed batch phase using a relative measurement method. By this approach, we eliminate the need of building a complex calibration model, which is time-consuming and requires an extensive knowledge of spectroscopy.
Subwavelength Structures for Interference Enhanced Attenuated Total Reflection Spectroscopy and its Application for Blood Analysis
Authors: L Sykora, A Müller, A Roth, S Kondratiev
Attenuated total reflectance (ATR) infrared absorption spectroscopy is a well-established analytical method. However, the sensitivity is limited compared to transmission measurements by the penetration depth of the evanescent wave. Innovative ATR Crystals with subwavelength pillars were made from silicon. First experiments show an enhancement factor of up to 20 compared to a standard single reflection diamond ATR element.
Workshop FT-IR Spectroscopy in Microbiological and Medical Diagnostics, 2017
ATR-FTIR Microplate Reader and Micromachined ATR Silicon Crystals
Authors: L Sykora, A Müller
The analysis of blood samples by Fourier Transform Infrared (FTIR) Spectroscopy to detect diseases like cancer or malaria are an upcoming topic in the last decades. There are ongoing efforts to transfer infrared spectroscopy from research into clinics.
Observing chemical reactions in real time is difficult. Mid-infrared spectroscopy offers the possibility to non-destructively monitor bond-specific changes at high speeds.
This application note describes the monitoring of fast reactions, ranging from timescales of milliseconds to minutes – using the IRsweep IRis-F1 spectrometer and the IRUBIS Universal ATR Crystal as a sensing substrate.
SEIRAS-optimized ATR Wafers for Interfacial Spectroelectrochemistry
Authors: TA Morhart, L Sykora, IJ Burgess
This application note shows that a microgrooved Si ATR wafer designed to allow high angles of incidence at the electrode-solution interface provides improved signal-to-noise in electrochemical ATR-SEIRAS.