Identification and determination of natamycin in fruit juice samples using HPLC

Abstract

Introduction: Since the use of preservatives in fruit juices is not allowed, it is important to monitor the presence of artificial preservatives to maintain the health of the consumer. In this study, for the first time, surfactant-assisted deep eutectic solvent-based salting-out homogenous liquid-liquid extraction performed in a narrow-bore tube has been introduced as a new sample pretreatment approach and used for the isolation of natamycin from fruit juices. Objective: Determination the amount of natamycin preservative in packaged juices using HPLC method. Methods: In this method, first tween 80 (as a surfactant) and a water-miscible ternary deep eutectic solvent composed of choline chloride: acetic acid: butanol (as an extractant) are added to the aqueous solution then homogenous state is formed. This solution is transferred into a narrow-bore tube and in the following, the homogenous solution is broken by addition of sodium chloride (as a phase separation agent). By this action, the analyte is extracted into the produced tiny droplets of extractant. This phase is quantified by high–performance liquid chromatography-ultraviolet detection. To obtain the best results, experimental conditions of developed extraction procedure are investigated and optimized by means of central composite design with variables including surfactant and extraction solvent volume, pH, and sodium chloride amount. Results: Under optimum conditions, low limits of determination and quantification (0.78 and 2.60 ng mL–1, respectively), acceptable repeatability (relative standard deviations of 4.9 and 7.1% for intra- and inter day precisions at a concentration of 25 ng mL–1), and high extraction recovery (76%) were obtained using the proposed method. Conclusion: At the end, the suggested method was effectively utilized for the analysis of natamycin in different juice samples.