Protonation of quinoline yellow WS in aqueous solutions: Spectroscopic and DFT theoretical studies

Removal of food dyes using biological materials via adsorption: A review

It is alarming that synthetic food dyes (FD) are widely used in various industries and that these facilities discharge their wastewater into the environment without treating it. FDs mixed into industrial wastewater pose a threat to the environment and human health. Therefore, removing FDs from wastewater is very important. This review explores the burgeoning field of FD removal from wastewater through adsorption using biological materials (BMs). By synthesizing a wealth of research findings, this comprehensive review elucidates the diverse array of BMs employed, ranging from algae and fungi to agricultural residues and microbial biomass. Furthermore, this review investigates challenges in practical applications, such as process optimization and scalability, offering insights into bridging the gap between laboratory successes and real-world implementations. Harnessing the remarkable adsorptive potential of BMs, this review presents a roadmap toward transformative solutions for FD removal, promising cleaner and safer production practices in the food and beverage industry.

Carbon-paste electrode modified by β-cyclodextrin as sensor for voltammetric determination of Tartrazine and Carmoisine from one drop

For food quality control methods, low cost, speed, and simplicity are essential. Electrochemical methods can satisfy all of these requirements. In this paper, we propose a fast and simple voltammetric method using a carbon-paste electrode modified with β-cyclodestrin for the determination of two common food azo dyes: Tartrazine and Carmoisine. To reduce the amount of sample required for analysis, in this work, we explored the prospect of another methodology similar to adsorption stripping voltammetry. The redox behavior of dyes, the influence of pH and scan rate on oxidation currents were investigated. Based on the results the scheme of oxidation of azo dyes was proposed. The use of the proposed approach in combination with the developed sensor makes it possible to determine Tartrazine and Carmoisine within their concentrations of 314-5024 ng/mL and 167-5340 ng/mL with calculation LOD 101 ng/mL and 60 ng/mL respectively. The proposed sensor was tested during analysis of model solutions and soft drinks and showed good results with high reproducibility.

Theoretical study on charge distribution in cetylpyridinium cationic surfactant

Here, we report the electrostatic potential maxima and partial atomic charges evaluated on cetylpyridinium cation. The Hartree-Fock method and six DFT functionals (namely, PBE, TPSS, B3LYP, PBE0, M06, and wB97) were used to calculate partial atomic charges via CHELPG, Mulliken, Löwdin, Hirshfeld, and natural population schemes. Calculations were performed for the gas phase and for the CPCM water solvated cation, resulting in a set of 70 types of partial atomic charges. The main tendencies in charge deviations were discussed. In comparison with the electrostatic potential-based CHELPG partial charges, Hirshfeld, Mulliken, Löwdin, and NPA partitioning schema lead to an almost steady decrease in the partial charges in the cetyl chain. This agreed closely with the redistribution of electrostatic potential mapped onto the 0.002 e/Bohr³ isodensity surface.