Elevated Temperature Homogeneous Liquid Phase Extraction Coupled to Ionic Liquid–Based Dispersive Liquid–Liquid Microextraction Followed by High-Performance Liquid Chromatography: Application of Water-Miscible Ionic Liquids as Extraction Solvent in Determination of Carbamate Pesticides

Abstract

In the present study, an elevated temperature homogeneous liquid extraction coupled with ionic liquid‑based dispersive liquid–liquid microextraction was developed to extract five carbamate pesticides (pirimicarb, carbaryl, methiocarb, aldicarb, and carbofuran) from packed fruit juice samples. The method consisted of a two-step procedure in which cyclohexylamine was used in order to extract the target analytes. In the first step, the analytes were extracted from a sample solution thermostated at elevated temperature (80 °C) into a water-immiscible organic solvent (cyclohexylamine). In the second step, the separated organic phase was mixed with 1-butyl-3-methylimidazolium chloride (as the solvent for extraction) and the mixture was spread into deionized water. In this step, cyclohexylamine controlled the solubility of 1-butyl-3-methylimidazolium chloride in the aqueous phase and acted as a dispersive solvent and a phase separation agent, simultaneously. After centrifugation, we removed all the gathered organic phases and analyzed them by using high-performance liquid chromatography diode-array detector. Figure of merits of the method including the limits of detection and quantification, enrichment factors, extraction recoveries, and relative standard deviations were obtained within ranges 0.4–3.9 and 1.5–13.2 ng mL−1, 147–217, 59–87%, and 3.3–5.5%, respectively, indicating that the method was successful in determining the analytes.