The ultratrace detection of crystal violet in fish and environmental water samples using cold-induced aggregation microextraction based on ionic liquid (IL-CIAME)

Abstract

A new method based on ionic liquid cold-induced aggregation microextraction (IL-CIAME) in combination with fiber optic-linear array detection spectrophotometry (FO-LADS) has been developed for the analysis of crystal violet (CV) in saline samples. In this methodology, a suitable temperature is used to fully dissolve very small amounts of 1-hexyl-3-methylimidazolium hexafluorophosphate [Hmim][PF₆] and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [Hmim][Tf₂N] as hydrophobic ionic liquids (ILs) and extractant solvents in the sample solution without the use of a disperser solvent. After dissolving, the solution was cooled in an ice bath and a cloudy solution of IL fine droplets was formed due to the decrease of IL solubility. After centrifuging, the fine droplets of the extractant phase settled to the bottom of the conical-bottom centrifuge tube. In this method, which is robust against high content of salt and water-miscible organic solvents, various parameters were investigated and optimized. Under the optimum conditions, the limit of detection (LOD) of the method was 1.16 μg L⁻¹ and the relative standard deviation (RSD) for 20 μg L⁻¹ CV was 2.30%. The obtained results indicated that the developed method is an excellent alternative for routine analysis in the environmental field.