"Thirteen samples of authentic absinthe dating from the preban era (i.e., prior to 1915) were analyzed for parameters that were
hypothesized as contributing to the toxicity of the spirit, including naturally occurring herbal essences (thujone, pinocamphone,
fenchone), methanol, higher alcohols, copper, and antimony. The total thujone content of preban absinthe was found to range between
0.5 and 48.3 mg/L, with an average concentration of 25.4 20.3 mg/L and a median concentration of 33.3 mg/L. The authors conclude
that the thujone concentration of preban absinthe was generally overestimated in the past. The analysis of postban (1915–1988) and
modern commercial absinthes (2003–2006) showed that the encompassed thujone ranges of all absinthes are quite similar,
disproving the supposition that a fundamental difference exists between preban and modern absinthes manufactured according to
historical recipes. Analyses of pinocamphone, fenchone, base spirits, copper, and antimony were inconspicuous. All things
considered, nothing besides ethanol was found in the absinthes that was able to explain the syndrome “absinthism”."
-- Abstract of the following article:
Chemical Composition of Vintage Preban Absinthe with Special Reference to
Thujone, Fenchone, Pinocamphone, Methanol, Copper, and Antimony
Concentrations
Published in Journal of Agricultural and Food Chemistry, April 2008