Hopanes, triterpenoid hydrocarbons formed under
geological conditions, were analysed to confirm the
mineral origin of the unresolved complex mixtures of
hydrocarbons observed in the gas chromatography with
flame ionization detection chromatograms of human
milk and certain foodstuffs. The ‘relative hopane content’
(RHC) is introduced, i.e. it is the area ratio of
the sum of the hopanes and the paraffins in the same
segment of the chromatogram. The RHC in various
mineral oil products (motor oils, hydraulic oils, lubricating
oils, Vaseline) was 3.4%, with a relative
standard deviation of 19%. The RHC determined in
samples of vegetable oils, mussels and clams as well
as of human milk containing an unresolved complex
mixture of hydrocarbons was in the same range,
confirming that these samples were contaminated by
mineral oil material.
