B. Fayet et al., CHARACTERIZATION AND QUANTITATIVE-DETERMI NATION OF TOCOPHEROLS AND GALLATES IN ESSENTIAL OILS, Sciences des aliments, 16(1), 1996, pp. 83-93
Antioxidants: butylhydroxyanisole, butylhydroxytoluene, propyl-, octyl
- and dodecyl- gallates, and natural or synthetic tocopherols, can be
legally used in essential oils with a maximal amount of 1 g . kg(-1).
Detection and quantitative determination of tocopherols and gallates r
equire specific analyses. High performance liquid chromatography (HPLC
) and capillary gas chromatography (GC) have been used to test 13 esse
ntial oils. HPLC chromatograms after direct injection of the essential
oils show, in most samples, peaks with retention times corresponding
to those of the studied antioxidants. However, the UV spectra recorded
on a photodiode array detector were different from the reference ones
. GC analyses for the tocopherols were carried out by direct injection
of samples, and after silylation fair the gallates. There was no inte
rference between the antioxidants and the essential oils constituents.
After optimization of the separation, the quantitative GC determinati
ons could be carried out using hexacosanol as internal standard for th
e alpha-tocopherol determination, and cholesterol in the case of the g
allates. The regression lines and correlation coefficients were determ
ined for alpha-tocopherol, and the propyl-, octyl-, dodecyl- gallates;
the detection limits were found to be respectively 120 and 60 mg . kg(
-1) for the alpha-tocopherol and the gallates.