Comparison of BTEX in Olive Oils by Static and Dynamic Headspace

The benefits of olive oil as part of a healthy diet reaches back to the 1950's. Methods were developed to determine benzene, toluene, ethylbenzene, xylenes and styrene (BTEXS) by static headspace methods. Both static and dynamic capabilities allow laboratories to characterize the volatile flavor components of olive oils and accurately quantify low levels of compounds like BTEXS.

Seven olive oil samples were obtained consisting of light flavor, pure, and extra virgin olive oils. Six were in glass containers, one in a plastic container. The countries of origin were indicated on the labels.

Experimental

The HT3 headspace instrument, to a Thermo Focus GC/DSQII MS and a Zebron ZB-624 30 m × 0.32 mm × 1.8 µm column was used. A Vocarb 3000 trap was used in the dynamic mode. The platen temperature was 90 °C for both methods.

The sample size was 10 g for the static analysis and 2 g for the dynamic analysis. BTEXS standards were used for identification.

Results

The BTEXS peak areas were determined from their primary quantitation ions. The peak areas were normalized for the olive oils and are presented in Table I. Figure 1 compares the static and dynamic headspace TIC for an olive oil samples.

Table I: Normalized data of seven olive oil samples

Conclusions

The data indicated similar results for all of these compounds except benzene. The dynamic mode detected higher concentrations of benzene in six of the seven olive oil samples.

Figure 1: Summed ion chromatograms of BTEXS ions for olive oil. Note the scale difference (NL Dynamic 5.5e7, NL Static 5.50e5).

References

(1) Teledyne Tekmar, Comparison of BTEXS in Olive Oils by Static and Dynamic HT3 Headspace.

Teledyne Tekmar

4736 Socialville Foster Rd., Mason, OH 45040

tel. (800) 874-2004

Website: www.tekmar.com.