The most important chemical constituents of safflower oil are methyl salicylate (from wintergreen oil), eugenol (from clove or cinnamon) and alpha-pinene (from turpentine). This has been recognized by the Ministry of Health of the People's Republic of China WS3-B-2699-97 [1] publication, and the Ministry of Health emphasizes that the content of these three components must pass before the safflower oil product is approved for public sale. The method of gas chromatography (GC) was used for quantification. According to this document, the minimum levels of methyl salicylate and eugenol are 33.5% v/v and 38% v/v, respectively. Poor quality safflower oil typically contains less eugenol, because clove and cinnamon must be much more expensive than wintergreen, and wintergreen oil is easily replaced with industrial methyl salicylate. Another possible source of poor quality is the doping of safflower oil by the addition of an excess of inert plants or paraffin oil.
In this document, we will present important information about the quality of safflower oil by visualizing the infrared spectrum, and the total analysis time is only a few minutes or even less. In another paper [2], we will establish accurate quantitative calibration curves for these three main components.
Experimental part
We used PerkinElmer's Spectrum Frontier Fourier Transform Infrared Spectrometer to acquire the infrared spectrum of the sample, which was used with the Attenuated Total Reflection (ATR) sampling accessory for 9 reflective diamond/zinc selenide crystals. The spectral acquisition resolution is 4cm-1 and the cumulative scan time is 60s.
Figure 1. The Frontier FT-IR
Results and discussion
Infrared spectra of pure compounds and some commercial samples
Figure 2 shows the molecular structure and infrared spectrum of methyl salicylate, eugenol and α-pinene, and the infrared spectra of two commercial safflower oil samples, sample A and sample B, OH and CH bonds. The amount of telescopic vibration information is particularly large. Although both methyl salicylate and eugenol contain a phenolic hydroxyl group, the stretching vibration frequency of methyl salicylate is approximately 3300 cm-1 or less. This is because the phenolic hydroxyl group combines with the hydrogen on the adjacent carbonyl to form intramolecular hydrogen bonds, which makes the two substances easily distinguishable by visualizing the infrared spectrum. Α-pinene can be identified by a very strong CH stretching vibration band, especially at 2916 cm-1, although the band overlaps with eugenol, but it cannot be distinguished from other hydrocarbons.
![]()
Figure 2. Molecular structure and infrared spectrum of major components in safflower oil (OH and CH stretching vibration regions) and infrared spectra of two commercial samples from different suppliers
in conclusion
The infrared spectrometer with the ATR sampling accessory gives a guiding measure of the quality of the safflower oil in less than a minute. Qualitative detection of infrared spectra makes it easy to identify important components such as methyl salicylate and eugenol.
references
1. State Food and Drug Administration of PRC WS3-B-
2699-97, Pharmaceutical Standard of Ministry of Health,
Prescription and Preparation of TCM (Z-14), Beijing:
People's Medical Publishing House, 1997.
2. Chen Jian-Bo, Zhou Qun, Sun Su-Qin, Ben Perston and
Patrick Courtney, "Quantitative Determination
Of Key Components in the Traditional Chinese Remedy
'Red Flower Oil' by FT-IR Spectroscopy" PerkinElmer
Application Note 009319_02.
For details, click the button below to request information.
Analog System
Analog System,Digital Analog System,Analog System And Digital System,Wifi Intercom
Zhuhai Mingke Electronics Technology Co., Ltd , https://www.mingke-tech.com