Published:Journal of Chromatographic Science,
ISSN 0021-9665Volume
39, Number 4, January 2001, pp. 137-145
Analysis
of Olive Oil and Seed Oil Triglycerides by Capillary Gas Chromatography as a
Tool for the Detection of the Adulteration of Olive OilN.K.
Andrikopoulos*
Harokopio University, Department of Science of Dietetics—Nutrition, 70
El. Venizelou Ave., 176 71 Kallithea, Athens, Greece
I.G. Giannakis and V. Tzamtzis
General State Chemical Laboratories, Food Division, 16 Tsocha Str., 115 21 Athens,
Greece
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.
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