Alkaline hydrolysis-UV activation strategy for rapid separation and screening of methyl salicylate in complex samples.

BACKGROUND: Methyl salicylate is an important volatile biomarker related to plant stress responses and is also widely used as an active ingredient in analgesic products. Rapid screening of methyl salicylate in complex samples is therefore valuable for agricultural monitoring and product quality assessment. In this study, a portable analytical method integrating alkaline hydrolysis, ultraviolet activation, gas membrane separation, and colorimetric derivatization was developed for methyl salicylate detection.

RESULTS: Methyl salicylate was hydrolyzed under alkaline conditions to generate methanol, which was subsequently oxidized by titanium dioxide under ultraviolet irradiation to produce formaldehyde. The generated formaldehyde was enriched through a gas membrane and derivatized with acetylacetone to form a yellow chromophore for ultraviolet-visible spectrophotometric quantification. Under optimized conditions, the method showed a linear response from 20 to 200 μg/mL, with a correlation coefficient of 0.9962 and a detection limit of 10.0 μg/mL. Recovery values were 105.1-113.0% for medical adhesive bandages and 85.5-115.0% for plant samples. Matrix blank tests showed no detectable background signal in the investigated real samples.

SIGNIFICANCE AND NOVELTY: The proposed method converts methyl salicylate into a detectable volatile derivative through a cascade reaction and combines chemical transformation with gas membrane enrichment in a portable workflow. Compared with conventional high-performance liquid chromatography, this method requires simpler instrumentation and is more suitable for rapid on-site screening. It provides a practical and field-deployable strategy for methyl salicylate analysis in medical products and plant samples.