| BACKGROUND: A new solvent, deep eutectic solvent, in which there is growing interest, has been prepared and used as an
extraction solvent in the dispersive liquid–liquid method of microextraction. To prepare the solvent, dichloroacetic acid, L-menthol, and n-butanol are mixed at a molar ratio of 4:1:1 and the deep eutectic solvent is formed after heating. Then a dispersive
liquid–liquid microextraction method using the prepared solvent is used for the extraction and preconcentration of some pesticides from an aqueous sample. To carry out the procedure, the deep eutectic solvent is mixed with methanol and rapidly
injected by a syringe into the aqueous sample containing the analytes. After centrifuging, an aliquot of the sedimented phase
is injected into the gas chromatograph. The influence of several variables on the extraction efficiency was investigated and
optimized.
RESULTS: Extraction recoveries and enrichment factors were obtained in the ranges of 53–86% and 1760–2853, respectively.
The intra- (n = 6) and inter-day (n = 5) precision of the method was satisfactory, with relative standard deviations ≤ 7%
obtained at two concentrations of 10 and 50 ∼g L−1 of each analyte. Moreover, detection and quantification limits for the target
analytes were obtained in the ranges of 0.11–0.23 and 0.38–0.74 ∼g L−1, respectively.
CONCLUSION: Different samples, including green tea, rose water, lemon balm, mint, and pussy willow distillates were analyzed
successfully using the method that was developed, and chlorpyrifos was found in rose water at a concentration of 17 ± 1 ∼g L−1
(n = 3) |