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White RL. Precise temperature control and rapid heating/cooling of infrared spectroscopy samples with a two-stage thermoelectric device. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2023. [PMID: 38047522 DOI: 10.1039/d3ay01627g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
The design and performance of an apparatus for heating and cooling samples during variable temperature infrared spectroscopy studies are described. The apparatus incorporates two thermoelectric device modules in a stacked configuration. The cascaded devices are powered in parallel and contained within a metal enclosure that maintains their alignment and applies clamping pressure between them to maximize thermal conductivity. By using this apparatus, sample temperatures can be increased or decreased at 2 °C s-1 rates and isothermal temperatures can be maintained precisely (±0.1 °C). The rapid heating and cooling capabilities of the apparatus facilitate programmed temperature step heating/cooling profiles with isothermal infrared spectrum measurements at pre-selected temperatures. Using linear heating and cooling temperature ramps, subtle temperature-dependent poly(styrene) infrared spectrum changes are elucidated and correlated with sample temperature. Results obtained by using a temperature step sample heating profile are compared with those obtained by using linear temperature ramp heating and cooling to characterize silica gel dehydration and re-hydration processes. By comparing infrared spectra acquired at different temperatures while heating and cooling the sample, silica gel spectrum changes associated with water desorption/adsorption and the thermal expansion/contraction of the Si-O-Si network are differentiated.
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Affiliation(s)
- Robert L White
- Department of Chemistry & Biochemistry, University of Oklahoma, 73069, USA.
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Böke JS, Popp J, Krafft C. Optical photothermal infrared spectroscopy with simultaneously acquired Raman spectroscopy for two-dimensional microplastic identification. Sci Rep 2022; 12:18785. [PMID: 36335148 PMCID: PMC9637219 DOI: 10.1038/s41598-022-23318-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 10/29/2022] [Indexed: 11/06/2022] Open
Abstract
In recent years, vibrational spectroscopic techniques based on Fourier transform infrared (FTIR) or Raman microspectroscopy have been suggested to fulfill the unmet need for microplastic particle detection and identification. Inter-system comparison of spectra from reference polymers enables assessing the reproducibility between instruments and advantages of emerging quantum cascade laser-based optical photothermal infrared (O-PTIR) spectroscopy. In our work, IR and Raman spectra of nine plastics, namely polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, silicone, polylactide acid and polymethylmethacrylate were simultaneously acquired using an O-PTIR microscope in non-contact, reflection mode. Comprehensive band assignments were presented. We determined the agreement of O-PTIR with standalone attenuated total reflection FTIR and Raman spectrometers based on the hit quality index (HQI) and introduced a two-dimensional identification (2D-HQI) approach using both Raman- and IR-HQIs. Finally, microplastic particles were prepared as test samples from known materials by wet grinding, O-PTIR data were collected and subjected to the 2D-HQI identification approach. We concluded that this framework offers improved material identification of microplastic particles in environmental, nutritious and biological matrices.
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Affiliation(s)
- Julia Sophie Böke
- grid.418907.30000 0004 0563 7158Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena, Germany
| | - Jürgen Popp
- grid.418907.30000 0004 0563 7158Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena, Germany ,grid.9613.d0000 0001 1939 2794Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Christoph Krafft
- grid.418907.30000 0004 0563 7158Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena, Germany
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Azam MS, Ranson MD, Hore DK. Temperature-Dependent Infrared Refractive Index of Polymers from a Calibrated Attenuated Total Reflection Infrared Measurement. APPLIED SPECTROSCOPY 2022; 76:1254-1262. [PMID: 35354313 PMCID: PMC9549256 DOI: 10.1177/00037028221094598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 03/16/2022] [Indexed: 06/14/2023]
Abstract
We demonstrate a straightforward method by which a commonly available reference sample such as water can be used to calibrate an attenuated total internal reflection infrared absorbance measurement in order to account for the polarization of the beam incident on the internal reflecting element, and the spread of angles about the nominal angle of incidence. This enables quantitative comparison of attenuated total reflection-derived absorbance data with spectra calculated from optical constants. We then apply this calibration to the measurement of temperature-dependent absorption spectra of a polydimethylsiloxane sample. We illustrate that the extracted optical constants scale with the temperature-dependent changes in the polymer density better than the raw absorbance values on vibrational resonance.
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Affiliation(s)
- Md S. Azam
- Department of Chemistry,
University
of Victoria, Victoria, BC, Canada
| | - Malcolm D. Ranson
- Department of Chemistry,
University
of Victoria, Victoria, BC, Canada
| | - Dennis K. Hore
- Department of Chemistry,
University
of Victoria, Victoria, BC, Canada
- Department of Computer Science,
University
of Victoria, Victoria, BC, Canada
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Shan P, Li Z, Wang Q, He Z, Wang S, Zhao Y, Wu Z, Peng S. Self-organizing maps-based generalized feature set selection for model adaption without reference data for batch process. Anal Chim Acta 2021; 1188:339205. [PMID: 34794558 DOI: 10.1016/j.aca.2021.339205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 12/01/2022]
Abstract
When fourier transform infrared spectroscopy (FTIR) techniques combined with multivariate calibration are used to measure the key process features or analyte concentrations during batch process, model adaption is indispensable for maintaining the predictability of a primary calibration model in new secondary batches. Many model adaption methods conforming to the actual application scenario of batch process have been proposed. Here we report on a novel standard-free model adaption method without reference measurement called variable selection strategy with self-organizing maps (VSSOM). It uses self-organizing maps (SOM) to classify the whole spectral variables into multiple classes according to the spectra from primary batch and secondary batch, respectively; and the corresponding primary feature subsets and secondary feature subsets are formed firstly. Secondly, candidate feature subsets without empty elements are generated by operating intersection between any primary feature subsets and any secondary feature subsets. Thirdly, the candidate feature subset with minimum root mean square error of cross-validation (RMSECV) for the primary calibration set is selected as the optimal feature subset. In this manner, the optimal feature subset can be identified from the candidate feature subsets. In other words, VSSOM aims to create a stable and consistent feature subset across different batches provided that it selects better features within the intersection sets between primary feature subsets and any secondary feature subsets. Two batch process datasets (γ-polyglutamic acid fermentation and paeoniflorin extraction) are presented for comparing the VSSOM method with No transfer partial least squares (PLS), boxcar signal transfer (BST), successive projection algorithm (SPA), transfer component analysis (TCA) and domain-invariant iterative partial least squares (DIPALS). Experimental results show that VSSOM has superior performance and comparable prediction performance in all the scenarios.
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Affiliation(s)
- Peng Shan
- College of Information Science and Engineering, Northeastern University, Shenyang, 110819, Liaoning Province, China.
| | - Zhigang Li
- College of Information Science and Engineering, Northeastern University, Shenyang, 110819, Liaoning Province, China
| | - Qiaoyun Wang
- College of Information Science and Engineering, Northeastern University, Shenyang, 110819, Liaoning Province, China
| | - Zhonghai He
- College of Information Science and Engineering, Northeastern University, Shenyang, 110819, Liaoning Province, China
| | - Shuyu Wang
- College of Information Science and Engineering, Northeastern University, Shenyang, 110819, Liaoning Province, China
| | - Yuhui Zhao
- School of Computer Science and Engineering, Northeastern University, Shenyang, 110819, Liaoning Province, China
| | - Zhui Wu
- College of Information Science and Engineering, Northeastern University, Shenyang, 110819, Liaoning Province, China
| | - Silong Peng
- Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China
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Park Y, Jin S, Park Y, Kim SM, Noda I, Chae B, Jung YM. Studies on Chemical IR Images of Poly(hydroxybutyrate⁻ co⁻hydroxyhexanoate)/Poly(ethylene glycol) Blends and Two-Dimensional Correlation Spectroscopy. Polymers (Basel) 2019; 11:polym11030507. [PMID: 30960491 PMCID: PMC6473784 DOI: 10.3390/polym11030507] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/06/2019] [Accepted: 03/13/2019] [Indexed: 11/24/2022] Open
Abstract
Biodegradable poly-[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoates] (PHBHx) have been widely studied for their applications in potentially replacing petroleum-based thermoplastics. In this study, the effect of the high molecular weight (Mn = 3400) poly(ethylene glycol) (PEG) blended in the films of PHBHx with different ratios of PEG was investigated using chemical FTIR imaging. Chemical IR images and FTIR spectra measured with increasing temperature revealed that PEG plays an important role in changing the kinetics of PHBHx crystallization. In addition, two-dimensional correlation spectra clearly showed that thermal properties of PHBHx/PEG blend film changed when the blending ratio of PHBHx/PEG were 60/40 and 50/50. Consequently, PEG leads to changes in the thermal behavior of PHBHx copolymers.
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Affiliation(s)
- Yeonju Park
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Korea.
| | - Sila Jin
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Korea.
| | - Yujeong Park
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Korea.
| | - Soo Min Kim
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Korea.
| | - Isao Noda
- Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, USA.
- Danimer Scientific, 140 Industrial Blvd., Bainbridge, GA 39817, USA.
| | - Boknam Chae
- Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Korea.
| | - Young Mee Jung
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Korea.
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Sobieski BJ, Gong L, Aubuchon SR, Noda I, Chase DB, Rabolt JF. Thermally reversible physical gels of poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate]: Part 1 gelation in dimethylformamide. POLYMER 2017. [DOI: 10.1016/j.polymer.2017.10.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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