4-Methoxymandelic acid: A leatherwood () honey marker for authentication.

Phenolic compounds in honey can serve as markers of authenticity for both botanical and geographical origins. Leatherwood () honey is a uniquely aromatic honey, only produced in Tasmania, Australia. This premium honey contains a distinctive array of phenolic markers useful for chemical fingerprinting. Thirty-two leatherwood honeys were analysed by HPLC-DAD, with samples collected over eight consecutive years and pooled on an annual basis. This study identified the presence of 28 phenolic compounds in leatherwood honey, with 14 compounds classified as potential markers for authentication. Most notably, this study identified, for the first time, 4-methoxymandelic acid using HPLC-Q-TOF/MS as the major phenolic substance in leatherwood honey. Further analysis revealed the presence of 4-methoxymandelic acid in nectar and thus a marker for the authentication of leatherwood honey.