Optimization of double-vortex-assisted matrix solid-phase dispersion for the rapid determination of paraben preservative residues in leafy vegetables

An environment-friendly approach using deep eutectic solvent combined with liquid-liquid microextraction based on solidification of floating organic droplets for simultaneous determination of preservatives in beverages

With the increase in environmental protection awareness, the development of strategies to reduce the use of organic solvent used during the extraction process has attracted wide attention. A simple and green ultrasound-assisted deep eutectic solvent extraction combined with liquid-liquid microextraction based on solidification of floating organic droplets method was developed and validated for the simultaneous determination of five preservatives (methyl paraben, ethyl paraben, propyl paraben, isopropyl paraben, isobutyl paraben) in beverages. Extraction conditions including the volume of DES, value of pH, and concentration of salt were statistically optimized through response surface methodology using a Box-Behnken design. Complex Green Analytical Procedure Index (ComplexGAPI) was successfully used to estimate the greenness of the developed method and compare with the previous methods. As a result, the established method was linear, precise, and accurate over the range of 0.5-20 μg mL^-1. Limits of detection and limits of quantification were in the range of 0.15-0.20 μg mL^-1 and 0.40-0.45 μg mL^-1, respectively. The recoveries of all five preservatives ranged from 85.96% to 110.25%, with relative standard deviation less than 6.88% (intra-day) and 4.93% (inter-day). The greenness of the present method is significantly better compared with the previous reported methods. Additionally, the proposed method was successfully applied to analysis of preservatives in beverages and is a potentially promising technique for drink matrices.

Dispersive solid phase extraction based on reduced graphene oxide modified Fe3O4 nanocomposite for trace determination of parabens in rock, soil, moss, seaweed, feces, and water samples from Horseshoe and Faure Islands

This study reports an efficient, green, sensitive and simple analytical protocol for trace determination of methyl paraben, ethyl paraben, propyl paraben, butylparaben and benzyl paraben by high-performance liquid chromatography-ultraviolet detection (HPLC-UV). The analytes were preconcentrated using an ultrasonication supported (US) dispersive solid phase extraction (DSPE) method based on reduced graphene oxide (rGO) modified iron nanoparticles (US-Fe₃O₄@rGO-DSPE). A reversed-phase C18 column and an isocratic elution program comprising of 20 mM phosphate buffer (pH 4.50) and acetonitrile(58:42, v/v) were used to elute and separate the analytes for detection. The limits of detection determined for the analytes were very low and were in the range of 0.02 - 0.16 ng mL^-1. The coefficients of determination obtained for the analytes ranged from 0.9973 to 0.9998, and this validated good linearity of the method.Percent relative standard deviations obtained in the range of 2.5 - 10.6% verified the method's high intraday repeatability. Accuracy of the proposed method was assessed with spiking experiments performed on complex sample matrices. Percent recoveries calculated for spiked soil, artificial seawater and seaweed samples were in acceptable ranges of 95 - 121%, 87 - 117% and 85 - 111%, respectively. These figures of merit suggest that HPLC-UV coupled with the US-Fe₃O₄@rGO-DSPEmethod is suitable for the determination of parabens in Antarctic samples.