**Section 3**

**FT-IR Spectroscopy** 

142 Macro to Nano Spectroscopy

Zhishen J, Mengcheng T, Jianming W. (1999). The determination of flavonoid contents in

64, pp. 555–559

mulberry and their scavenging effects on superoxide radicals. Food Chemistry, Vol.

**9** 

*Romania* 

**Organic Compounds FT-IR Spectroscopy** 

*National Institute for Research and Development in Electrochemistry and* 

General spectral range of electromagnetic radiation with a wavelength greater than 750 nm (i.e. with the number of wavelength below 13000 cm-1) bears the name of the domain infrared (IR). In this field samples absorb electromagnetic radiation due to transitions of vibration of the structure of molecules, molecular transitions in vibrations crystalline network (if the sample is in the solid state of aggregation) or due to transitions of molecular rotation. Subdomain of spectral wavelengths between 2500 - 50000 nm (respectively the

From the point of view of analytical control of medicinal products, this domain is the most used. At the base of absorption is being generated electromagnetic radiation in this area spectral transitions are the vibrations of individual molecules or of crystalline network (if the sample examined is solid). Show effects such transitions caused by the vibrations of individual molecules provides information about molecular structure of the sample examined, and show effects such crystalline network to identify a particular forms of

The most frequent use of the absorption spectrophototometry in the middle infrared field lies in the identification of substances through molecular vibration. The wavelength (i.e, the wave numbers) of the of the absorption band are characteristic chemical identity of the substance in question. The intensity of the absorption bands allows quantitative analysis of the samples but, unlike in the ultraviolet and visible, in the infrared field diffuse radiation is much more refreshing, and for this reason quantitative determination infrared, are affected

From the standpoint of analytical use, the spectra of molecular vibration is enjoying increased popularity in comparison to the study of the crystal latice's vibrations. A molecule may be considered to be a vibrator with more than one degree of freedom, able to execute more modes of vibration. In each mode of vibration every atom in the molecule oscillates about their own position of equilibrium. Such oscillations have different amplitudes for

wave numbers 4000 to 200 cm-1) bears the name of the *middle infrared domain.* 

**1. Introduction** 

by notable errors.

\* Corresponding Author

crystallization of the substance of interest.

Anamaria Dabici, Paula Sfirloaga and Zoltan Szabadai

Adina Elena Segneanu, Ioan Gozescu\*,

*Condensed Matter, Timisoara (INCEMC-Timisoara)* 
