A New Possibility of the Generalized Two-Dimensional Correlation Spectroscopy. 2. Sample−Sample and Wavenumber−Wavenumber Correlations of Temperature-Dependent Near-Infrared Spectra of Oleic Acid in the Pure Liquid State

2000 ◽  
Vol 104 (27) ◽  
pp. 6388-6394 ◽  
Author(s):  
Slobodan Šašić ◽  
Andrzej Muszynski ◽  
Yukihiro Ozaki
Keyword(s):  
Oleic Acid ◽  
Infrared Spectra ◽  
Liquid State ◽  
Near Infrared ◽  
Correlation Spectroscopy ◽  
Pure Liquid ◽  
Two Dimensional ◽  
Temperature Dependent ◽  
Near Infrared Spectra

Band Analysis of Temperature-Dependent Near-Infrared Spectra of Oleic Acid in the Pure Liquid State by the Analytic Geometric Approach

2003 ◽  
Vol 57 (12) ◽  
pp. 1539-1550 ◽  
Author(s):  
Katsue Koashi ◽  
Makio Iwahashi ◽  
Yukihiro Ozaki
Keyword(s):  
Oleic Acid ◽  
Infrared Spectra ◽  
Liquid State ◽  
Near Infrared ◽  
Geometric Approach ◽  
Pure Liquid ◽  
Temperature Dependent ◽  
Near Infrared Spectra

Analysis of Near-Infrared Spectra of Complicated Biological Fluids by Two-Dimensional Correlation Spectroscopy: Protein and Fat Concentration-Dependent Spectral Changes of Milk

1999 ◽  
Vol 53 (12) ◽  
pp. 1582-1594 ◽  
Author(s):  
Bogusława Czarnik-Matusewicz ◽  
Koichi Murayama ◽  
Roumianna Tsenkova ◽  
Yukihiro Ozaki
Keyword(s):  
Infrared Spectra ◽  
Near Infrared ◽  
Biological Fluids ◽  
Correlation Spectroscopy ◽  
Two Dimensional ◽  
Spectral Changes ◽  
Near Infrared Spectra

Two-Dimensional Infrared and Near-Infrared Correlation Spectroscopy: Applications to Studies of Temperature-Dependent Spectral Variations of Self-Associated Molecules

1997 ◽  
Vol 51 (4) ◽  
pp. 526-535 ◽  
Author(s):  
Yukihiro Ozaki ◽  
Yongliang Liu ◽  
Isao Noda
Keyword(s):  
Near Infrared ◽  
Oleyl Alcohol ◽  
Correlation Spectroscopy ◽  
Intensity Change ◽  
Pure Liquid ◽  
Two Dimensional ◽  
Temperature Dependent ◽  
Thermally Induced ◽  
2D Ir ◽  
Almost All

This paper demonstrates the potential of generalized two-dimensional (2D) Fourier transform (FT) infrared (IR) and near-infrared (NIR) correlation spectroscopy in the studies of temperature-dependent spectral variations of self-associated molecules. Three examples of the 2D correlation analysis are discussed in this paper. The first two are concerned with the temperature-dependent IR and NIR spectral changes of N-methylacetamide (NMA) in the pure liquid state. The 2D IR correlation approach revealed that almost all the peaks of NMA in the 3400–1100-cm−1 region consist of two to four separate bands. For example, the amide I band contains contributions from at least four distinct bands at 1685, 1665, 1650, and 1635 cm−1. The analysis of the asynchronous 2D IR spectrum in the amide I region showed that the sequence of spectral intensity change in the ascending order of temperature was given by 1635<1650<1665<1685 cm−1. These bands at 1635, 1650, 1665, and 1685 cm−1 were assigned to the amide I modes of chain oligomers of various sizes and dimer of NMA; the longer the chain, the lower the frequency. The closeup view of 2D NIR correlation spectra of NMA obtained at narrow spectral and temperature windows enabled us to propose not only band assignments in the 6800–6050-cm−1 region but also a detailed mechanistic picture of the thermally induced dissociation of NMA for each temperature range. We also applied the generalized 2D correlation approach to the analysis of a set of FT NIR spectra of oleyl alcohol under temperature variations. The 2D NIR analysis enhanced the spectral resolution and simplified the spectra with overlapped bands. For example, it was found that a band at 7090 cm−1 arising from the first overtone of an OH stretching mode of the monomeric alcohol consists of two bands due to the rotational isomerism of the free OH group. An intriguing possibility of correlating various overtone and fundamental bands to establish unambiguous assignments was also suggested from the 2D NIR study on oleyl alcohol.

The use of two-dimensional spectroscopy to interpret the effect of temperature on the near infrared spectra of whisky

2020 ◽  
Vol 28 (3) ◽  
pp. 148-152 ◽  
Author(s):  
Ishita Joshi ◽  
Vi Khanh Truong ◽  
J Chapman ◽  
D Cozzolino
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Infrared Region ◽  
Correlation Spectroscopy ◽  
Alcoholic Beverages ◽  
Effect Of Temperature ◽  
Two Dimensional ◽  
Near Infrared Spectra

The variations in temperature during the analysis of alcoholic beverages are of importance to develop protocols based on near infrared spectroscopy. The objective of this study was to evaluate the effect of increasing temperature on the near infrared spectra of whisky samples using two-dimensional correlation spectroscopy. Whisky samples from different commercial labels were analyzed at four different temperatures (25°C, 35°C, 45°C, and 55°C) using a UV–VIS–NIR instrument. Asynchronous and synchronous two-dimensional correlation spectroscopy was used to reveal the effect of temperature on the near infrared spectra of the samples. The results of this study indicated that temperatures between 40°C and 55°C alter absorption at specific wavelengths in the near infrared region of the whisky samples analyzed. The combination of near infrared spectroscopy with two-dimensional correlation spectroscopy has the potential to dramatically improve the efficiency of analytical laboratories, considering the range of data that can be collected.

Potential of Generalised Two-Dimensional Correlation Spectroscopy in the near Infrared Region

1996 ◽  
Vol 4 (1) ◽  
pp. 85-99 ◽  
Author(s):  
Yukihiro Ozaki ◽  
Isao Noda
Keyword(s):  
Near Infrared ◽  
Infrared Region ◽  
Carbonyl Oxygen ◽  
Correlation Spectroscopy ◽  
Pure Liquid ◽  
Two Dimensional ◽  
Temperature Dependent ◽  
Thermally Induced ◽  
Correlation Spectrum ◽  
Nylon 12

This review demonstrates the potential of generalised two-dimensional (2D) correlation spectroscopy in the near infrared (NIR) region. Three examples of generalised 2D NIR correlation analysis, which are all concerned with the temperature-dependent spectral variations of self-associated molecules, are discussed in this paper. The first example presents the 2D correlation approach to the analysis of a set of NIR spectra of oleyl alcohol in the pure liquid state under temperature changes. The 2D NIR analysis enhances the spectral resolution and simplifies the spectra with overlapped bands. For example, it was found that a band at 7090 cm−1, arising from the first overtone of an OH stretching mode of the monomeric alcohol, consists of two bands due to the rotational isomerism of the free OH group. The second example deals with the temperature-dependent NIR spectral changes of N-methylacetamide (NMA). The close-up view of 2D NIR correlation spectra of NMA, obtained at narrow spectral and temperature windows, enabled us to propose not only band assignments in the 6800–6050 cm−1 region, where the first overtones of stretching modes of free, free-end and hydrogen-bonded NH groups were expected to appear, but also a detailed mechanistic picture of the thermally-induced dissociation of NMA for each temperature range. A 2D NIR study of premelting behaviour and hydrogen bonds of Nylon 12 is discussed as the third example. The asynchronous 2D NIR correlation spectrum of Nylon 12 obtained from 30 to 150°C in the 6900–6100 cm−1 region indicated that the amide group with a free carbonyl oxygen appears first and then the unassociated free amide and amide with free NH follow as the temperature is increased. The asynchronous spectrum in the 6000–5500 cm−1 region, where the first overtones of the CH2 stretching modes are expected to appear, suggested that a substantial amount of disordered or dissociated components start appearing before the disappearance of more ordered components. It seemed that they appear as the premelting precursors (or even possibly as the indirect cause) to the precipitous decrease of the ordered components associated with the melting of Nylon 12 occurring at a much higher temperature.

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