2.7 Raman Spectroscopy Lab Report

2.7 Raman spectroscopy
Principle: Raman spectroscopy is based on the use of a laser light to induce oscillation and rotation in human fluids containing glucose. Because the emission of scattered light is influenced by molecular vibration, it is possible to estimate glucose concentration in human fluids [24]. This effect depends on the concentration of the glucose molecules. This technique can measure very weak signals, even in human fluids. The wavelength range of Raman spectrum is considered to be 200 cm−1 to 2,000 cm−1.35 Raman spectrum of glucose can be differentiated from those of other compounds in this band.
Advantages: Raman spectroscopy usually provides sharper and less overlapped spectra compared to NIR spectroscopy. The intensity of spectral features is proportional to the concentration of the particular species, and the
While this approach has theoretical potential, it seems that no further works has been done since Lee’s group reported their laboratory results on rat skin [27]. A variation, named photoacoustic spectroscopy, is being used, which is based on the use of a laser light for the excitation of a fluid and for measuring the resulting acoustic response [28]. The fluid is excited by a short laser pulse with a wavelength that is absorbed by a particular molecular species in the fluid. Light absorption causes microscopic localized heating in the medium, which generates an ultrasound pressure wave that is detected by a microphone. The principle of the photoacoustic method is that an energy source irradiates the skin surface, causing thermal expansion in the illuminated area. An acoustic wave releases because of the energy of the thermal expansion. The detection of glucose with this technique is based on measuring the changes of the peak to-peak value of the signal, which varies according to the glucose content of the