Fast dispersive liquid–liquid microextraction based on magnetic retrieval of in situ formed an ionic liquid for the preconcentration and determination of benzophenone-type UV filters from environmental water samples

Abstract

This work concerns the development of a novel and rapid in situ dispersive liquid–liquid microextraction method for magnetic retrieval of ionic liquid as a new approach for the separation of benzophenone type (BP-type) UV filters via quantification using UPLC with PDA detection. The analytes determined in this study were a group of three benzophenones: 2,4-dihydroxybenzophenone (BP1), 2,2′,4,4′-tetrahydroxybenzophenone (BP2) and 2-hydroxy-4-metoxybenzophenone (BP3). The hydrophilic ionic liquid found suitable for use as an extraction solvent of the targeted analytes was didecyldimethylammonium chlorate (DDAC). An anion exchanger, NaClO 4 was added to promote a metathesis reaction and in situ formed the IL, [DDA][ClO 4 ]. The experimental parameters such as the concentration of IL, the molar ratio of DDAC to NaClO 4 , amount of iron oxide added and volume of water sample were investigated and optimised using a step-by-step optimisation process. The optimum experimental parameters were as follows: 30 mL of sample volume, 1% concentration of DDAC, the molar ratio of DDAC to NaClO 4 —1:2, and 5 mg of Fe 3 O 4 magnetic nanoparticles. The proposed extraction method is simple and requires no more than 5 min. The detection limit (LOD) obtained for target analytes ranged from 12.320.0 ng L −1 , while the correlation coefficient (r 2 ) was from 0.9995 to 0.9999. Finally, the developed method was successfully applied to the determination of BP-type UV filters in environmental water samples, and satisfactory results were obtained.