Glycerol of recent biological origin can be differentiated from that produced from archaic sources of carbon, e.g. mineral oil or coal products, by measuring the 14C content by liquid scintillation counting.
In the case of synthetic glycerol derived from archaic carbon the count rate, i.e. background, was independent of the amount of sample added, while with natural glycerol the count rate increases linearly with the amount of sample. It is possible to detect 15% of natural glycerol in admixture with synthetic glycerol with a confidence of 99%.