Preparation of deep-eutectic solvent and study on the detecting methods of crystal violet by deep-eutectic solvent

Abstract

This paper prepared deep eutectic solvent using choline chloride (hydrogen bond acceptor) and phenol (hydrogen bond donor) as raw materials in molar ratio of 1:3. The prepared DES showed hydrophobic properties, sodium carboxymethyl cellulose was used as an emulsifier to pretreat crystal violet (CV), and the prepared DES was used as an excellent extractant to extract CV for detection. Ultraviolet spectrophotometry was used to determine the absorbance of CV after extraction to calculate the corresponding extraction concentration. In addition, the influences of external influencing factors, such as appropriate extractant and emulsifier, required centrifugation time, and proper pH on the experimental results were also explored. Under the optimized conditions, the detected content of CV (pH = 4, centrifugation time 10 min) showed good linear relationship in the range of 5∼40 mg/L, the limit of detection (LOD) and quantification (LOQ) were 1.01 μg/L and 1.53 μg/L. The proposed method was applied to blue frame label paper and blue ball ink commonly used in the laboratory as the determination method of marking experiments. As a result, the recovery rates obtained were more than 80 %, confirming the feasibility of the proposed method.