Development of a liquid-phase micro-extraction based on the use of deep eutectic solvent for pre-concentration and measurement of malachite green in water and fish samples

Abstract

ABSTRACT An easy-to-use, fast, and efficient liquid phase micro-extraction was developed based on the use of a deep eutectic solvent to extract malachite green (MG) from the water and fish samples. Herein, a green solvent including choline chloride (ChCl): phenol (PhOH) with a ratio of 1:3 was tested as an extractant phase in dispersive liquid-liquid micro-extraction for MG extraction followed by spectrophotometric determination. A 15 ml portion of the sample solution was used, and various effective parameters for the deep eutectic solvent (DES) in the micro-extraction models, such as deep eutectic solvent volume, salt concentration, time of micro-extraction, and pH were assayed and optimised. The best micro-extraction cases were collected by 186 microlitres of deep eutectic solvent, a salt concentration of 1.2% W/V, a pH of 4.5 of samples, and a micro-extraction time of 5.5 min. Multi-layer perceptron was also used to train the network. R2 and mean square error (MSE) are 0.9965 and 1.8968 respectively. In optimal values, the linear range of malachite green was achieved to be 10–350 ng mL−1. Enrichment factor and LOD were reached to be 60 and 2 ng mL−1, respectively. The %RSD of 100 ng mL−1 of malachite green was 2.6%. Finally, this method allows the measurement of MG in fish and aqueous samples with favourable recoveries.