Near-Infrared Raman Spectroscopy Using CCD Detection and a Semiconductor Bandgap Filter for Rayleigh Line Rejection

1992 ◽  
Vol 46 (6) ◽  
pp. 891-893 ◽  
Author(s):  
Alfons Schulte
Keyword(s):  
Raman Spectroscopy ◽  
Fourier Transform ◽  
Raman Spectra ◽  
Near Infrared ◽  
Sapphire Laser ◽  
Laser Line ◽  
Rayleigh Line ◽  
Rejection Filter ◽  
Multichannel Detection ◽  
Fourier Transform Raman

A novel application of a tuneable Ti: sapphire laser and a CdTe Rayleigh line rejection filter for near-infrared Raman spectroscopy employing a single grating spectrograph and multichannel detection is demonstrated. Raman spectra of liquid, solid, and photobiological samples have been measured within 75 cm−1 of the exciting laser line. At excitation wavelengths between 790 and 850 nm, a significant improvement in sensitivity over that for present Fourier transform Raman techniques has been obtained.

Potential of Near-Infrared Fourier Transform Raman Spectroscopy in Food Analysis

1992 ◽  
Vol 46 (10) ◽  
pp. 1503-1507 ◽  
Author(s):  
Y. Ozaki ◽  
R. Cho ◽  
K. Ikegaya ◽  
S. Muraishi ◽  
K. Kawauchi
Keyword(s):  
Raman Spectroscopy ◽  
Fourier Transform ◽  
Fatty Acid ◽  
Raman Spectra ◽  
Food Analysis ◽  
Near Infrared ◽  
Egg White ◽  
Ft Raman Spectroscopy ◽  
Ft Raman

The 1064-nm excited Fourier transform (FT) Raman spectra have been measured in situ for various foods in order to investigate the potential of near-infrared (NIR) FT-Raman spectroscopy in food analysis. It is demonstrated here that NIR FT-Raman spectroscopy is a very powerful technique for (1) detecting selectively the trace components in foodstuffs, (2) estimating the degree of unsaturation of fatty acids included in foods, (3) investigating the structure of food components, and (4) monitoring changes in the quality of foods. Carotenoids included in foods give two intense bands near 1530 and 1160 cm−1 via the pre-resonance Raman effect in the NIR FT-Raman spectra, and therefore, the NIR FT-Raman technique can be employed to detect them nondestructively. Foods consisting largely of lipids such as oils, tallow, and butter show bands near 1658 and 1443 cm−1 due to C=C stretching modes of cis unsaturated fatty acid parts and CH2 scissoring modes of saturated fatty acid parts, respectively. It has been found that there is a linear correlation for various kinds of lipid-containing foods between the iodine value (number) and the intensity ratio of two bands at 1658 and 1443 cm−1 ( I1658/ I1443), indicating that the ratio can be used as a practical indicator for estimating the unsaturation level of a wide range of lipid-containing foods. A comparison of the Raman spectra of raw and boiled egg white shows that the amide I band shifts from 1666 to 1677 cm−1 and the intensity of the amide III band at 1275 cm−1 decreases upon boiling. These observations indicate that most α-helix structure changes into unordered structure in the proteins constituting egg white upon boiling. The NIR FT-Raman spectrum of old-leaf (about one year old) Japanese tea has been compared with that of its new leaf. The intensity ratio of two bands at 1529 and 1446 cm−1 ( I1529/ I1446), assignable to carotenoid and proteins, respectively, is considerably smaller in the former than in the latter, indicating that the ratio is useful for monitoring the changes in the quality of Japanese tea.

Application of near-infrared-Fourier transform Raman spectroscopy in medical research

1994 ◽  
Vol 25 (7-8) ◽  
pp. 663-671 ◽  
Author(s):  
Stefan Keller ◽  
Bernhard Schrader ◽  
Andreas Hoffmann ◽  
Wolfgang Schrader ◽  
Klaus Metz ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Fourier Transform ◽  
Medical Research ◽  
Near Infrared ◽  
Fourier Transform Raman Spectroscopy ◽  
Fourier Transform Raman
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