Determination of Acetylsalicylic Acid and Salicylic Acid in Foods, Using HPLC with Fluorescence Detection

Abstract

We developed a specific and sensitive HPLC method with fluorescence detection for the determination of free acetylsalicylic acid, free salicylic acid, and free salicylic acid plus salicylic acid after alkaline hydrolysis (free-plus-bound) in foods. Acetylsalicylic acid was detected after postcolumn hydrolysis to salicylic acid. With the method for free acetylsalicylic acid and salicylic acid, recovery was 95-98% for acetylsalicylic acid added to foods and 92-102% for salicylic acid. Recovery of added salicylic acid was 79-94% for the free-plus-bound salicylic acid method. The limit of detection was 0.02 mg/kg for fresh and 0.2 mg/kg for dried foods for all substances. We did not find acetylsalicylic acid in any of 30 foods previously thought to be high in salicylates. The contents of free-plus-bound salicylic acid and of free salicylic acid ranged from 0 to 1 mg/kg in vegetables and fruits and from 3 to 28 mg/kg in herbs and spices. Thus the tested foods did not contain acetylsalicylic acid and only small amounts of salicylic acid. Our data suggest that the average daily intake of acetylsalicylic acid from foods is nil and that of salicylic acid is 0-5 mg/day.