Dispersive liquid-liquid microextraction of pesticides and metabolites from soils using 1,3-dipentylimidazolium hexafluorophosphate ionic liquid as an alternative extraction solvent

In this work, the use of the ionic liquid (IL) 1,3-dipentylimidazolium hexafluorophosphate (PPIm]PF?]) as an alternative extractant for IL dispersive liquid-liquid microextraction (IL-DLLME) of a group of pesticides and metabolites (2-aminobenzimidazole, carbendazim/benomyl, thiabendazole, fuberidazole, carbaryl, 1-naphthol, and triazophos) from soils is described. After performing an initial ultrasound-assisted extraction (USE), the IL-DLLME procedure was applied for the extraction of these organic analytes from soil extracts. Separation and quantification was achieved by high-performance liquid chromatography (HPLC) with fluorescence detection (FD). Calibration, precision, and accuracy of the described USE-IL-DLLME-HPLC-FD method using PPIm]PF?] as an alternative extractant was evaluated with two soils of different physicochemical properties. Accuracy percentages were in the range 93-118% with RSD values below 20%. A comparison of the performance of PPIm]PF?] versus that of the so-common 1-hexyl-3-methylimidazolium hexafluorophosphate (HMIm]PF?]) was accomplished. Results indicate a comparable extraction efficiency with both ILs, being slightly higher with HMIm]PF?] for the metabolite 2-aminobenzimidazole, and slightly higher with PPIm]PF?] for triazophos. In all cases, LODs were in the low ng/g range (0.02-14.2 ng/g for HMIm]PF?] and 0.02-60.5 ng/g for PPIm]PF?]). As a result, the current work constitutes a starting point for the use of the IL PPIm]PF?] for further analytical approaches.