第33卷，第12期 2013年12月
光谱学与光谱分析 Spectroscopy and Spectral Analysis
Vol.33,No.12-pp3240-3243
December : 2013
Raman Spectra of Oleic Acid and Linoleic Acid
FAN Ya', LI Shuang' , XU Da-peng
1 . School of Science , Changchun U niversity of Science and Technology , Changchun 130022 , China 2 . College of Physics , Jilin University , Changchun 130012, China
Abstract Different unsaturated fatty acids have different physiological functions , however , the common fatty acid products are mostly mixture of several unsaturated fatty acids . Thus it is necessary to analyze the compo sition of impure fatty acid products before application . In the present article , the Raman spectra of oleic acid and linoleic acid (the most commonly appearing components of fatty acid products ) were measured . Further-more , the mode assignments of the Raman bands were determined and the molecular conformational characters were analyzed . The results lay the groundwork for researching the energy level structures and transitions of long-chain unsaturated fatty acids and enrich the valence bond data of organic molecules . In addition, the differenoes between the Raman spectra of oleic acid and linoleic acid were analyzed in detail , which provides a convenient and effective method for their identification and has directive significance for the application of Raman spectroscopy in hogwash oil detection .
KeywordsOleic acid ; Linoleic acid ; Raman spectroscopy
中图分类号：0433
Introduction
文献标识码：A
DOI ; 10. 3964/j. issn. 1000-0593 (2013)12-3240-04
functions required are quite different .
Raman spectroscopy is widely applied as a detecting means of matter structure[5-8] . And it is more advantageous
Unsaturated fatty acids are the fatty acids whose mole -cules possess one or more carbon double bonds . Oleic acid is the most common monounsaturated fatty acid . Linoleic acid is one kind of polyunsaturated fatty acids and well-known essen-tial fatty acid , which is required but cannot be synthesized by themselves , and must be supplied in the diet . As important diet fatty acids , monounsaturated and polyunsaturated fatty acids each have specific physiological functions . For example , monounsaturated fatty acids can lower the blood sugar () , and protect the heart[2] , And polyunsaturated fatty acids can low -er the contents of triglyceride and cholesterol in serum , and thereby decrease the incidence of cardiovascular diseases [s.] However , owing to the difficulty in the separation of long-chain unsaturated fatty acids , the common fatty acid products are mostly mixture of several fatty acids . Thus it is necessary to analyze the composition of impure fatty acid products be-fore application under the condition that the physiological
Received : 2013-07-28 ; aceepted : 2013-09-30
than other methods in the detection of biological sample be-cause it is non-traumatic, has no special request for sample preparation , and requires fewer samples . Thus in this article oleic acid and linoleic acid were experimentally studied and distinguished via Raman spectroscopy -
Experimental
The liquid samples of oleic acid and linoleic acid with pu. rity above 99% were purchased from SIGM A Co . Ltd .
Raman spectra measurements of both oleic acid and lino -leic acid were performed with a Raman microscope (Jobin Yvon, HR800) equipped with an Ar+ laser (514.5 nm, 20 mW) and a multiple track CCD detector . The slit width was 50 μm and grating line was 1 800. The micro lens was * 50 normal lens and the integration time was 20 s , Frequency cali-bration of the Raman spectrum was realized with the characteristic
Foundation item : Project supported by the National Science Foundation of China (61006065 , 11204020)
Biography : FAN Ya, female , (1981—), Lecturer at Changchun University of Science and Technology
e-mail ; bnucaro@163.com