Real-time liquid-phase organic reaction monitoring with mid-infrared attenuated total reflectance dual frequency comb spectroscopy

Real-time information about milk composition would be very useful for managing the milking process. Mid-infrared spectroscopy, which relies on fundamental modes of molecular vibrations, is routinely used for off-line analysis of milk and the purpose of the present study was to investigate the potential of attenuated total reflectance mid-infrared spectroscopy for real-time analysis of milk in milking lines. The study was conducted with 189 samples from over 70 cows that were collected during an 18 months period. Principal component analysis, wavelets and neural networks were used to develop various models for predicting protein and fat concentration. Although reasonable protein models were obtained for some seasonal sub-datasets (determination errors <~0·15% protein), the models lacked robustness and it was not possible to develop a model suitable for all the data. Determination of fat concentration proved even more problematic and the determination errors remained unacceptably large regardless of the sub-dataset analyzed or of the spectral intervals used. These poor results can be explained by the limited penetration depth of the mid-infrared radiation that causes the spectra to be very sensitive to the presence of fat globules or fat biofilms in the boundary layer that forms at the interface between the milk and the crystal that serves both as radiation waveguide and sensing element. Since manipulations such as homogenisation are not permissible for in-line analysis, these results show that the potential of mid-infrared attenuated total reflectance spectroscopy for in-line milk analysis is indeed quite limited.

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ATTENUATED TOTAL REFLECTANCE SPECTROSCOPY OF LIQUIDS USING A MID-IR DUAL FREQUENCY COMB SPECTROMETER

Proceedings of the 73rd International Symposium on Molecular Spectroscopy ◽

10.15278/isms.2018.ta09 ◽

2018 ◽

Author(s):

Daniel Herman ◽

Ian Coddington ◽

Nathan Newbury ◽

Esther Baumann ◽

Fabrizio Giorgetta ◽

...

Keyword(s):

Frequency Comb ◽

Reflectance Spectroscopy ◽

Attenuated Total Reflectance ◽

Dual Frequency ◽

Total Reflectance ◽

Attenuated Total Reflectance Spectroscopy

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Mid-Infrared Dual-Comb Spectroscopy of Liquid-Phase Samples using Attenuated Total Reflectance

Conference on Lasers and Electro-Optics ◽

10.1364/cleo_si.2018.sth1l.2 ◽

2018 ◽

Author(s):

D. Herman ◽

G. Ycas ◽

F. R. Giorgetta ◽

E. Waxman ◽

E. Baumann ◽

...

Keyword(s):

Liquid Phase ◽

Attenuated Total Reflectance ◽

Mid Infrared ◽

Total Reflectance

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Infrared Fiber-Optic Spectroscopy Detects Bovine Articular Cartilage Degeneration

Cartilage ◽

10.1177/1947603521993221 ◽

2021 ◽

pp. 194760352199322

Author(s):

Vesa Virtanen ◽

Ervin Nippolainen ◽

Rubina Shaikh ◽

Isaac O. Afara ◽

Juha Töyräs ◽

...

Keyword(s):

Support Vector Machine ◽

Infrared Spectroscopy ◽

Articular Cartilage ◽

Fiber Optic ◽

Mechanical Damage ◽

Attenuated Total Reflectance ◽

Support Vector ◽

Mid Infrared ◽

Total Reflectance ◽

Joint Injuries

Objective Joint injuries may lead to degeneration of cartilage tissue and initiate development of posttraumatic osteoarthritis. Arthroscopic surgeries can be used to treat joint injuries, but arthroscopic evaluation of articular cartilage quality is subjective. Fourier transform infrared spectroscopy combined with fiber optics and attenuated total reflectance crystal could be used for the assessment of tissue quality during arthroscopy. We hypothesize that fiber-optic mid-infrared spectroscopy can detect enzymatically and mechanically induced damage similar to changes occurring during progression of osteoarthritis. Design Bovine patellar cartilage plugs were extracted and degraded enzymatically and mechanically. Adjacent untreated samples were utilized as controls. Enzymatic degradation was done using collagenase and trypsin enzymes. Mechanical damage was induced by (1) dropping a weight impactor on the cartilage plugs and (2) abrading the cartilage surface with a rotating sandpaper. Fiber-optic mid-infrared spectroscopic measurements were conducted before and after treatments, and spectral changes were assessed with random forest, partial least squares discriminant analysis, and support vector machine classifiers. Results All models had excellent classification performance for detecting the different enzymatic and mechanical damage on cartilage matrix. Random forest models achieved accuracies between 90.3% and 77.8%, while partial least squares model accuracies ranged from 95.8% to 84.7%, and support vector machine accuracies from 91.7% to 80.6%. Conclusions The results suggest that fiber-optic Fourier transform infrared spectroscopy attenuated total reflectance spectroscopy is a viable way to detect minor and major degeneration of articular cartilage. Objective measures provided by fiber-optic spectroscopic methods could improve arthroscopic evaluation of cartilage damage.

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Detection of adulterants in grape nectars by attenuated total reflectance Fourier-transform mid-infrared spectroscopy and multivariate classification strategies

Food Chemistry ◽

10.1016/j.foodchem.2018.06.006 ◽

2018 ◽

Vol 266 ◽

pp. 254-261 ◽

Cited By ~ 18

Author(s):

Carolina Sheng Whei Miaw ◽

Marcelo Martins Sena ◽

Scheilla Vitorino Carvalho de Souza ◽

Maria Pilar Callao ◽

Itziar Ruisanchez

Keyword(s):

Fourier Transform ◽

Infrared Spectroscopy ◽

Attenuated Total Reflectance ◽

Multivariate Classification ◽

Mid Infrared ◽

Total Reflectance ◽

Mid Infrared Spectroscopy

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Comparison of Attenuated Total Reflectance Mid-Infrared, Near Infrared, and 1H-Nuclear Magnetic Resonance Spectroscopies for the Determination of Coffee’s Geographical Origin

International Journal of Analytical Chemistry ◽

10.1155/2017/7210463 ◽

2017 ◽

Vol 2017 ◽

pp. 1-8 ◽

Cited By ~ 10

Author(s):

Jessica Medina ◽

Diana Caro Rodríguez ◽

Victoria A. Arana ◽

Andrés Bernal ◽

Pierre Esseiva ◽

...

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Near Infrared ◽

Geographical Origin ◽

Fraud Detection ◽

Attenuated Total Reflectance ◽

Mid Infrared ◽

Total Reflectance ◽

H Nmr

The sensorial properties of Colombian coffee are renowned worldwide, which is reflected in its market value. This raises the threat of fraud by adulteration using coffee grains from other countries, thus creating a demand for robust and cost-effective methods for the determination of geographical origin of coffee samples. Spectroscopic techniques such as Nuclear Magnetic Resonance (NMR), near infrared (NIR), and mid-infrared (mIR) have arisen as strong candidates for the task. Although a body of work exists that reports on their individual performances, a faithful comparison has not been established yet. We evaluated the performance of 1H-NMR, Attenuated Total Reflectance mIR (ATR-mIR), and NIR applied to fraud detection in Colombian coffee. For each technique, we built classification models for discrimination by species (C. arabica versus C. canephora (or robusta)) and by origin (Colombia versus other C. arabica) using a common set of coffee samples. All techniques successfully discriminated samples by species, as expected. Regarding origin determination, ATR-mIR and 1H-NMR showed comparable capacity to discriminate Colombian coffee samples, while NIR fell short by comparison. In conclusion, ATR-mIR, a less common technique in the field of coffee adulteration and fraud detection, emerges as a strong candidate, faster and with lower cost compared to 1H-NMR and more discriminating compared to NIR.

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