Validated Method for Quantitation and Identification of 4,4-Desmethylsterols and Triterpene Diols in Plant Oils by Thin-Layer Chromatography–High Resolution Gas Chromatography–Mass Spectrometry

Abstract

Alkaline hydrolysis was performed on a series of different vegetable oils. The unsaponifiable lipid matter was extracted with ethyl ether, and the class of 4,4-desmethylsterols (sterols) plus the triterpene diols (diols) erythrodiol, uvaol, and betulinol were isolated by thin-layer chromatography. A validated method using the acetate derivatives of sterols instead of their silyl ethers is presented. The acetate derivatives were analyzed by high resolution gas chromatography (HRGC). Retention time, precision, recovery studies, and absolute response factors were calculated for these esters, and GC/mass spectrometric structure of the assigned retention times was confirmed for the sterols and triterpene diols.

Profiling of Phytosterols, Tocopherols and Tocotrienols in Selected Seed Oils from Botswana by GC–MS and HPLC

“…The results from this analysis were contrasted with the results of the second level, which involved determination of the absolute amounts of 4-desmethylsterols obtained from SPE fractionation of the unsaponifiable matter from each of the seed oils before GC-MS analysis. At both levels of analysis acetate derivatives of the sterols were preferred to trimethylsilyl (TMS) derivatives, because acetylated derivatives are more stable and enable easier detection of side-chain unsaturation in the sterol molecules, and also enable easier distinction between D 5 and D 7 phytosterols [19].…”

“…1. The absolute amount of each identifiable 4-desmethylsterol was calculated as lg/g of the seed oil by using the relationship, 4-desmethylsterol = (A z 9 m is )/(A is 9 m), where A z = start peak area, A is = internal standard peak area, m is = mass (lg) of internal standard, and m = mass of oil in g weighed for the analysis [19]. The results obtained from the analysis are shown in Table 3, and agree very closely with the results shown in Table 2 for the general phytosterol profiles of the test seed oils.…”

The Influence of Growing Region, Cultivar and Harvest Timing on the Diversity of Australian Olive Oil

“…Erythrodiol levels are high in solvent extracted or refined oils (i.e. pomace oils) and therefore high levels in virgin oils would indicate adulteration with pomace oil [14].…”

Fatty acids, volatiles, sterols and triterpenic alcohols of six monovarietal Tunisian virgin olive oils

“…It is noteworthy that the sterol and alcohol profiles have been proposed as applicable to the characterization of olive oil [6,7]. Hence, the sterol composition and the level of erythrodiol and uvaol are often used to detect the presence of other vegetable oils or olive pomace in virgin olive oil and to check its genuineness [8,9].…”