Choline chloride-L-lactic acid mixtures as solvents for extraction of Coumarin from cinnamon-containing foods

Abstract

The determination of coumarin in generally available cinnamon-containing foods such as biscuits, cereals is important to ensure that the populations consuming these foods more frequently are not exposed to higher levels and are not at risk. This study describes the development of an analytical method for determination of coumarin in foods containing cinnamon. Solid-liquid phase extraction with conventional stirring-assisted procedure and ultrasound-assisted extraction (UAE) procedures were used to prepare sample extracts for liquid chromatography analysis. The green solvent, a mixture of choline chloride:L-lactic acid (1:4, mol/mol)/water (50:50 v/v), as a deep eutectic solvent-like mixture, was selected as an extraction solvent. The extraction conditions were optimized by using the design of the experiment strategy that resulted in values, temperature 47 °C, time 36 min, solvent volume 4 mL, sample amount 0.8 g, stirring speed 20 rpm for rotary stirring-assisted extraction procedure, and temperature 30 °C, time 5 min, solvent volume 3.5 mL, sample amount 0.8 g for UAE. High-performance liquid chromatography separation with a total analysis time of 12 min was performed with a stationary phase of octadecyl type and a gradient of mobile phase of methanol-1 % acetic acid. The methods were successfully validated to show the detection limit of 0.13 μg.mL−1, the linearity range of 0.4–50 µg.mL−1 (R2 = 0.999), recovery rates of more than 80 %, and the RSDs of less than 7 %. Rotary stirring-assisted extraction showed moderately higher recovery values than UAE, while lower RSD % was observed for UAE.