A green ternary polymeric deep eutectic solvent used in dispersive liquid-liquid microextraction technique for isolation of multiclass pesticides in fruit juice samples

A green dispersive liquid-liquid microextraction procedure based on a ternary polymeric hydrophobic deep eutectic solvent (DES) for monitoring multi-residue pesticides in eleven various fruit juices was developed before Gas Chromatography coupled with micro-Electron Capture Detector (GC-& mu;ECD). Six ternary polyethylene glycol (PEG)-based DESs were synthesized, and their extraction efficiency was evaluated. Among these DESs, [thymol]: [polyethylene glycol]:[acetic acid] (1:2:2) showed the highest signal intensity. Moreover, three other binary PEG-based DESs and a non-polymeric DES were also synthesized and compared to the previous DES. The extraction yield obtained by polymeric one was much higher than non-polymeric. Some significant parameters influencing the extraction efficiency including the type and volume of DES (extraction solvent), disperser solvent, pH, and ionic strength were optimized as follows: [Thy]:[PEG]:[HOAc] (1:2:2), 400 & mu;L of DES, ACN as disperser solvent (700 & mu;L), no pH adjustment and no salt addition. The DES was characterized by ATR-FTIR and (1H and 13C) NMR spectroscopy. Under the optimized conditions, the limits of quantification, the linear ranges and extraction recovery were 0.009-0.182 & mu;gL-1 0.003-50.0 & mu;gL-1, 67.9-108.4%, respectively. The enrichment factors were 11-170. Intra-day and inter-day RSDs% were 1.4-5.1% and 2.0-12.6%, respectively. This method was applied for analyzing pesticide residues in eleven fruit juices, and the pre-concentration factor and relative extraction recoveries were in the range of 12-169 and 71-108%, respectively.

Automated summary

A green dispersive liquid-liquid microextraction method based on a ternary polymeric hydrophobic deep eutectic solvent was developed for monitoring multi-residue pesticides in fruit juices. The method showed low limits of quantification, high linear ranges, and good extraction recoveries under optimized conditions. The effect of different parameters on the extraction efficiency was evaluated and the optimal conditions were determined.