Near Infrared Spectra Of Organic Compounds

A Novel Diagnostic Method for Human Immunodeficiency Virus Type‐1 in Plasma by Near‐Infrared Spectroscopy

“…This is due to the various absorption bands of water. The peak near 970 nm was previously assigned to the second overtone of the O-H stretching mode (15,32). As a strong band is observed in the 600-700 nm region for water, the peak in the 600-700 nm region may also be due to water absorption.…”

The Absorption Behavior of Water and Some Organic Liquids in the Near Infrared Studied by Photoacoustic Spectroscopy

“…2300 nm to 2600 nm ( Fig. 1) are due to C -H combination vibrations [12,13]. The matching combinations of C -D vibrations, however, would be outside the region of observation (above 2600 nm).…”

“…Consequently, the charac teristic features in their NIR spectra are overtones and combinations of the stretching and deformation modes of the O -H and the C -H groups. For alcohols, the first and second overtone of the O -H stretching vibration should occur at about 1.4 pm and 0.9 pm, respectively, whereas the combination band appears at about 2.1 pm [9][10][11][12][13], The funda mental C -H stretching vibration gives rise to an absorption band at about 3.3 pm to 3.5 pm, and the first and second overtone at about 1.7 pm and 1.2 pm, respectively [9][10][11][12][13]. Another band with relatively high intensity exists near 2.3 pm, which belongs to the second overtone of the carbonhydrogen "bending" vibration at about 6.9 pm [10,12,13].…”

“…Figure 4 shows, e.g., the PA-spectrum of benzene in the NIR. Besides the first, second and third overtone of the C -H stretching vibration, the spectrum contains two absorption bands at 2155 nm and 2450 nm, which can be assigned to C -H combination vibra tions [1,5,12]. The peak positions /" of the n-th stretching overtone n vCH are in rather good agree ment with the results of Patel et al [14], They deter mined the positions of the C -H overtone n = 1 to n = 5 of benzene by conventional spectrophotometry and obtained: for n = 2: (1671.4 ± 0.6) nm, for n = 3: (1141.6 ± 0.3) nm and for n = 4: (874 ± 0.2) nm.…”

Ex vivo Tissue Discrimination by Visible and Near-Infrared Spectra with Chemometrics

“…Based on the first three loadings (Fig. 2C) and the peaks ( [15,26], and are commonly observed in PC1 (950 nm), PC2 (930, 940, 960 nm) and PC3 (940, 960 nm). The peaks around 750 nm have reported elements existing close to a water band, and are accordingly observed in PC1 (760 nm), PC2 (740, 760 nm) and PC3 (740, 760 nm).…”