Handshake of deep eutectic solvent and ionic liquid: Two liquid-liquid microextraction procedures for plant analysis

Plants are subjects of interest due to the secondary metabolites in their extracts which are promising as new pharmaceuticals. Phytochemistry do not have united system of sample preparation or analysis still due to different structure of plant cells, wide broad range of chemical properties and concentrations of bioactive compounds. Such challenges can be addressed in a green chemistry manner using new approaches through smart materials in routine monitoring and researches. Liquid smart materials, such as ionic liquids (ILs) and deep eutectic solvents (DESs) are attractive due to flexible properties, lots of extraction approaches, recycle potential, and direct compatibility with powerful analytical methods. In this study DES-based microextraction procedure with pH-switching was developed. Four choline chloride DESs were suggested as selective extraction phases for polar compounds from acetonitrile extracts. Method was successfully tested on four plants (Iris sibirica L., Hypericum perforatum L., Scutellaria baicalensis G, Citrus reticulata B.). Developed procedure was optimized and validated for the choline chloride - urea (1:2 mol/mol) DES that demonstrated better results in extraction. LOD for rutin was found as 0.05 mg ml-1. For low-polar compound, imidazolium ionic liquid-based dispersive liquid-liquid microextraction procedure was developed. 1-hexyl-3-methylimidazolium salts have demonstrated desired selectivity. The main factors influencing the extraction efficiency have been identified and optimized by design of experiment on two model plants (Iris sibirica L. and Scutellaria baicalensis G.). Validation procedures were done for thymol. LOD for thymol was found as 0.021 mg ml-1. The methods were compared with each other and traditional methanol extraction. The selectivity of the smart materials supports each other, usage of such extraction phases provides same or better results as obtained with methanol.

Extraction of parabens from personal care products using a pH-responsive hydrophobic deep eutectic solvent: experimental design and COSMO-RS evaluations

A pH-responsive hydrophobic deep eutectic solvent is used for the extraction of parabens from different personal care products.

Strategies to improve the challenges of classic dispersive liquid-liquid microextraction for determination of the parabens in personal care products-One step closer to green analytical chemistry

Gas flow-assisted dispersive liquid-phase microextraction based on deep eutectic solvent was used to determine parabens in personal care products such as mouthwash, lidocaine gel, aloe vera gel, and skin tonic. A homemade extraction device was innovated, in which by passing the stream of gas bubbles through the deep eutectic solvent a thin layer of the extraction phase is coated on the surface of the bubbles. The extraction is finally achieved when the bubbles are going up through the sample. The single-factor experiments and response surface methodology were applied to optimize the independent variables. The linear range of the method was 0.5 to 1000 µg L^-1, the coefficient of determination for the goal analytes was higher than 0.9989, the instrumental limit of detections were in the range 0.2-0.3 μg L^-1, and the instrumental limit of quantifications were in the range 0.5-1.1 μg L^-1, the relative standard deviations were <5.2% for repeatability and <11.2% for intermediate precision, and the enrichment factors were 66 to 87 obtained under the optimized conditions. A spiking approach by means of standard material was used to estimate accuracy. The relative recoveries were in the range 95.8-105.2%. By using mentioned strategies, the organic waste and energy consumption reduced, toxic reagents replaced with safer ones, and operator safety enhanced. Accordingly, these benefits have been simultaneously attained and, the proposed method was one step closer to automation and sustainable analytical chemistry.

In-Syringe Micro Solid-Phase Extraction Method for the Separation and Preconcentration of Parabens in Environmental Water Samples

In this study, a simple, rapid and effective in-syringe micro-solid phase extraction (MSPE) method was developed for the separation and preconcetration of parabens (methyl, ethyl, propyl and butyl paraben) in environmental water samples. The parabens were determined and quantified using high performance liquid chromatography and a photo diode array detector (HPLC-PDA). Chitosan-coated activated carbon (CAC) was used as the sorbent in the in-syringe MSPE device. A response surface methodology based on central composite design was used for the optimization of factors (eluent solvent type, eluent volume, number of elution cycles, sample volume, sample pH) affecting the extraction efficiency of the preconcentration procedure. The adsorbent used displayed excellent absorption performance and the adsorption capacity ranged from 227–256 mg g⁻¹. Under the optimal conditions the dynamic linear ranges for the parabens were between 0.04 and 380 µg L⁻¹. The limits of detection and quantification ranged from 6–15 ng L⁻¹ and 20–50 ng L⁻¹, respectively. The intraday (repeatability) and interday (reproducibility) precisions expressed as relative standard deviations (%RSD) were below 5%. Furthermore, the in-syringe MSPE/HPLC procedure was validated using spiked wastewater and tap water samples and the recoveries ranged between from 96.7 to 107%. In conclusion, CAC based in-syringe MSPE method demonstrated great potential for preconcentration of parabens in complex environmental water.