Analysis of Olive Oil and Seed Oil Triglycerides by Capillary Gas Chromatography as a Tool for the Detection of the Adulteration of Olive Oil

Abstract

Individual triglyceride (TG) species of olive oil and several seed oils (corn, cottonseed, palm, peanut, soybean, and sunflower) are baseline separated on a WCOT TAP CB fused-silica capillary column by capillary gas chromatography (CGC) with a flame-ionization detector (FID) and either cold on-column or split injection. An adulteration of olive oil with a low content (< 5%) of these seed oils (except peanut oil) can be verified by the detection of the increasing levels of trilinolein or tripalmitin in olive oil in which these TG species are normally absent or present at very low levels (< 0.5%). An adulteration with over 20% peanut oil can be detected by the increasing levels of palmitodilinolein. TG species that can be coeluted with trilinolein in the reversed-phase high-performance liquid chromatographic (RP-HPLC) mode are baseline separated by the CGC technique, and their structures are identified by selective ion monitoring mass spectrometry. The following comparisons--the CGC-FID and RP-HPLC methods for detection of adulteration, cold on-column and split-injection modes for CGC-FID, and silylation or thin-layer chromatography pretreatment and simple dilution of one or more of the oil samples--are also presented. The normalized percentage area of the TG species is sufficient for the method limits used in this study. Mixtures of virgin olive oil with refined or residue olive oil could not be distinguished from the virgin type by the method used in this study.

Rapid Determination of Degradation of Frying Oil Using Near-Infrared Spectroscopy

“…These methods are relatively easy to use but are not suitable for monitoring chemical changes in frying oils during deep-fat frying. Techniques such as high-performance liquid chromatography (HPLC) and gas chromatography (GC) have also been used for identifying adulterants, but these are expensive and time-consuming (Andrikopoulos et al, 2001).…”

Determination of the cultivar and aging of Sicilian olive oils using HPLC‐MS and linear discriminant analysis

“…On the basis of triacylglyceridic content, several methods have been developed in order to distinguish between different vegetable edible oils, [24,25] or different grade olive oils (from extra virgin to lower quality oils).…”

The Detection and Quantification of Adulteration in Olive Oil by Near-Infrared Spectroscopy and Chemometrics

“…Techniques such as high-performance liquid chromatography (HPLC) and gas chromatography (GC) 6 have also been used in identifying adulterants. 6 These techniques are expensive and time consuming.…”

“…6 These techniques are expensive and time consuming. There have been several attempts to find more rapid and efficient methods for the detection of olive-oil adulteration.…”