Deep eutectic solvent based method for analysis of Niclosamide in pharmaceutical and wastewater samples – A green analytical chemistry approach

Abstract

The paper presents a simple, but very effective and sensitive spectrophotometric method for trace analysis of Niclosamide based on liquid–liquid microextraction using deep eutectic solvents (DESs) prior to its quantification. Here, different DES systems, such as Choline chloride (ChCl) + Urea, ChCl + Citric acid, ChCl + Ethylene glycol and ChCl + Phenol, were synthesized and evaluated at different molar ratios, selecting ChCl + Phenol 1:2 as an extractive DES system. Optimization studies revealed that best performance were obtained at pH 8 with optimum volume of THF and DES as 0.3 mL and 0.4 mL, respectively. The developed method is characterized by good analytical performance, e.g., a recovery of 99.26% and precision described by RSD value as <2%. The inter-assay precision was 0.51% while intermediate precision was 0.0323%. The method was found linear from 4.8 to 48 µg/L. LOD and LOQ were found as 0.112 and 0.374 µg/L, respectively. The paper presents also examples of the application of the proposed method for the determination of Niclosamide in different pharmaceutical and wastewater samples. This alternative method reveals a better performance in respect to the British pharmacopoeia procedure, providing concurrently ease of operation and simplicity.