Influence of temperature on mass transfer in an incomplete trapping supported liquid membrane extraction of triazole fungicides

Abstract

The influence of temperature in a supported liquid membrane (SLM) extraction of triazole fungicides was investigated. The mass transfer parameters such as diffusion coefficient, flux and apparent viscosity were determined at temperatures ranging from 5 to 40 degrees C. Increase in temperature led to an increase in diffusion coefficient and flux with a flowing acceptor solution. The apparent viscosity also decreased with an increase in temperature. However, the increase in mass transfer parameters did not result in an overall increase in extraction efficiency with a stagnant or circulation acceptor phase. Stripping of the analytes from the membrane into the acceptor phase as well as the configuration of the extraction unit could have limited the influence of temperature on mass transfer. The partition coefficient of analytes from the acceptor solution to the membrane, K(A), was found to be much higher than that from the donor solution to the membrane K(D), thus triazole compounds preferred to remain in the membrane even with an increased extraction temperature.

Determination of acid dissociation constants of triazole fungicides by pressure assisted capillary electrophoresis

“…Usage of these corrections results in 0.14-0.5 pH unit decrease of pK a values as compared to pK a values calculated from the non-corrected effective mobilities. For comparison, the values of the acid dissociation constants of the triazole fungicides and the 1,2,4-triazole itself calculated by SPARC online calculator [39] and pK a s found in the literature [8,14,40,41] are also listed in this Table. The pK a s determined by pCE in this work are slightly higher than the values calculated by SPARC online calculator [39]. The highest difference between the calculated and the experimentally determined pK a was observed for flusilazole, which contains silicon atom in its structure.…”

Optimization of Ultrasonic-Assisted Extraction of Total Phenolics from Citrus aurantium L. Blossoms and Evaluation of Free Radical Scavenging, Anti-HMG-CoA Reductase Activities

“…In general, the higher the extraction temperature, the higher is the extraction yield, which is due to the fact that molecules move faster at higher temperature, leading to enhanced diffusion and permeation behaviors [28]. However, if the extraction temperature is too high, the heat-sensitive components would be destroyed.…”

Optimization of Ultrasonic-Assisted Extraction of Total Phenolics from Citrus aurantium L. Blossoms and Evaluation of Free Radical Scavenging, Anti-HMG-CoA Reductase Activities

“…In general, the higher extraction temperature, the higher extraction yield, which is due to the fact that molecules move faster at higher temperature, leading enhanced diffusion and permeation behaviors [30]. But if the extraction temperature is too high, the heat-sensitive components would be destroyed.…”

“…Ultrasonic-assisted extraction of total phenolics from CAB was carried out with an ultrasonic apparatus (KQ-5200DE, Kunshan ultrasonic Co. Ltd., Suzhou, China), and ultrasound frequency and ultrasound power were set as 40 kHz and 100 W, respectively. Each 5 g of sample powder was placed into a volumetric flask (250 mL), then extracted with various ethanol concentrations (30, 40 50, 60, 70, 80%), temperatures (30,40,50,60, 70, 80 °C), liquid-solid ratio (15,20,25,30,35, 40 mL/g) for various times (15, 30, 45, 60, 75, 90 min) respectively. The extracts were filtered, combined, after which extraction solvent was replenished to bring the final volume of the extract to 250 mL.…”