Cyanide profiling in stone fruit syrups: A comparative study of distillation techniques, a novel derivatization method, and cyanide composition in Maesil (Prunus Mume) syrup

Cyanide ion was derivatized with o-phthalaldehyde and 3-mercaptopropionic acid for high-performance liquid chromatography-diode array detector analysis. The structure was elucidated using nuclear magnetic resonance spectroscopy and ultra-high performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry. Method validation was conducted for three distillation methods to analyze cyanogenic glycosides, cyanohydrins, and free cyanide in fruit syrup. Acid-aided distillation only detected free cyanide, while direct distillation detected both free cyanide and cyanohydrins, and enzyme-aided distillation reflected all three types. These approaches were applied to stone fruit syrups in South Korean markets and households. Among tested, maesil (Prunus mume) syrup contained the highest amount of total cyanide, reaching a maximum of 21.9 mg/kg (cyanide ion equivalent), compared to other syrups. Investigation of cyanide composition changes during maesil syrup production revealed that free cyanide occupies the lowest proportion. Cyanogenic glycosides degraded gradually during aging, while cyanohydrins remained the majority after 12 months aging.