*2.4.2 Instrumentation*

Instrumentation for modern Raman spectroscopy consists of following components:


The (**Table 1**) one shows some common laser sources which are generally use in Raman Spectroscopy [29] and (**Figure 13**) shows the instrumentation of Raman Spectrophotometer [30].


**Table 1.**

*Some common laser sources for Raman spectroscopy.*

**Figure 13.** *Instrumentation of Raman spectrometer.*

### *2.4.3 Raman spectrum*

Typically Raman spectrum is plotted signal intensity vs. Raman shift (Raman shift, in cm−1 = energy of photon in − energy of photon out). **Figure 14** shows the Raman spectrum.

### *2.4.4 Applications*


**Figure 14.** *Raman Spectrum.*

*Spectroscopy and Spectrophotometry: principles and Applications for Colorimetric and Related… DOI: http://dx.doi.org/10.5772/intechopen.101106*

structure of biomolecules, cells, and tissues. This approach is very helpful for the scientists to diagnose the malignant neoplasm which leads to the cervical cancer [32].


#### **2.5 Spectro-fluorometry**

#### *2.5.1 Principle*

The phenomenon, where a molecule after absorbing radiations emits radiation of a longer wavelength, is known as fluorescence. When a compound absorbs radiation, it goes to the exited level and thereafter comes to the ground level either in one step by emitting radiation of the same wavelength that it absorbed or in a stepwise manner by emitting quanta of radiation corresponding to each energy step with longer wavelength. This phenomenon leads to the formation of fluorescence spectra. Fluorescence is an extremely short-lived phenomenon (10−7 s or less) and therefore can provide information about events which takes less than 10−7 s. Fluorometry also follow the Beer-Lambert law in its working principle.

#### *2.5.2 Instrumentation*

Fluorometry is an important analytical tool for the determination of extremely small concentrations of substances which exhibit fluorescence.

#### *2.5.3 Instrumentation*

The instrumentation of a spectrofluorometer differs from that of the spectrophotometer in two important respects besides other minor variations.

**Figure 15.**

*Instrumentation of spectrofluorometer.*


The main components of a spectrofluorometer indicated in **Figure 15** are:

### *2.5.4 Applications*


*Spectroscopy and Spectrophotometry: principles and Applications for Colorimetric and Related… DOI: http://dx.doi.org/10.5772/intechopen.101106*

**Figure 16.**

*Development of vitamin A fluorescence spectra acquired on milk samples after heating at 55°C and 75°C during 10 min.*
