Development and optimization of natural deep eutectic solvent-based dispersive liquid-liquid microextraction coupled with UPLC-UV for simultaneous determination of parabens in personal care products: evaluation of the eco-friendliness level of the developed method.

Dispersive liquid-liquid microextraction (DLLME) combined with ultra-high performance liquid chromatography-diode array detector (UHPLC-DAD) method has been developed and validated for the determination of parabens in personal care products. In this study, a natural deep eutectic solvent (NADES) composed of menthol and formic acid at a molar ratio of 1 : 2 was prepared and used as an extraction solvent. The influencing variables on the extraction efficiency such as extraction solvent type and volume, composition of NADES, salt addition, vortex and centrifugation time were investigated. The proposed method exhibited good linearity with determination coefficients of ≥0.9992. The relative recoveries for the studied analytes ranged from 82.19 to 102.45%. Limits of detection and limits of quantification were in the range of 0.17-0.33 ng mL-1 and 0.51-0.99 ng mL-1, respectively. To evaluate the applicability of the developed method, it was successfully applied to determine four parabens in personal care products. Additionally, the eco-friendliness level of the presented method was evaluated using Eco-Scale Assessment, Green Analytical Procedure Index and Analytical GREEnness metric. The developed method is simple, environmentally friendly and cost effective and it could be employed for determination of parabens in personal care products without harming the environment.

Treatment of Tannery Effluent Using a Rotating Disc Electrochemical Reactor.

A novel rotating disc electrochemical (RDE) reactor has been developed to treat tannery effluent. Experiments were carried out in batch, batch recirculation, and once-through modes in the reactor covering wide range of operating conditions. The effect of current density (i), cathode rotation speed (R), electrolysis time (t), influent pH, and electrolyte flow rate (Q) on the pollutant removal efficiency and specific energy consumption was critically evaluated. The response of the process parameters were measured in terms of percentage total organic carbon (TOC) removal. The reaction mechanism of electro-oxidation was modeled using first-order kinetics. GC-MS and FT-IR analysis of the raw and treated effluent show that the tannery effluent can be effectively treated using the RDE reactor.