Kinetic exploration supplemented by spectroscopic and molecular docking analysis in search of the optimal conditions for effective degradation of malachite green

Abstract

The degradation of malachite green (MG) by an alkaline hydrolytic process has been explored spectrophotometrically. The kinetics of the reaction have been meticulously studied under the influence of cationic alkyltrimethylammonium bromide (DTAB, TTAB and CTAB) surfactants, a-, band gcyclodextrins (CDs) and surfactant-b-CD mixed systems applying pseudo-first order conditions at 298 K. The surfactants and cyclodextrins individually catalyze the hydrolytic rate, whereas surfactant-b-CD mixed systems exhibit both an inhibiting and catalytic influence depending on the surfactant concentrations. The kinetic results have been explained precisely based on the pseudo-phase ion exchange (PIE) model of micelles and CD-catalyzed model of CD systems. The surfactants exhibit micellar surface catalysis, while CDs accelerate the rate by forming MG-CD inclusion complexes, thereby facilitating nucleophilic attack of its ionized secondary hydroxyl group on the carbocation center of MG. The encapsulation of MG within the supramolecular host cavity of the CDs has been investigated diligently using a steady-state absorption spectroscopic technique. The result shows 1 : 1 host-guest complexation with different relative orientations of the guest (MG) inside the hosts. Studies employing density functional theory (DFT) as well as molecular docking analysis provide valuable insight on the insertion mechanism. The results reveal that quantitative analysis can be utilized to predict the optimum conditions for the fastest degradation of MG in ambient environments.Fig. 2 Plots of k obs versus [CD] 0 for the reaction of MG and À OH in aqueous medium at 298 K. [MG] 0 ¼ 1.25 Â 10 À5 M, [ À OH] 0 ¼ 1.875 mM. Inset: catalytic factor (k max obs /k w ) in different cyclodextrin systems at fixed [CD] ¼ 1.0 mM. Scheme 3 Hydrolysis of MG in aqueous solution of CD.This journal is

Organic additives stabilize RNA aptamer binding of malachite green

“…This stabilization is beneficial for MGA-based applications towards accurate and repeatable detection assays based on MG's fluorescence enhancement by MGA [30,31]. Finally, a synergistic stabilization mechanism is proposed based on both fluorescence and absorbance kinetics combined with previous reports on MG kinetics in aqueous environments [32,33].…”

Unfinished Recipes: Structuring Upper-Division Laboratory Work To Scaffold Experimental Design Skills

“…Micelles are known to influence reaction kinetics by either separating or containing together reactants, and indeed, kinetics of reactions in the presence of micelles have been reported in this Journal. 25 However, in this case, students were directed to a recent research study exploring hydrolysis kinetics in the absence and presence of micelles 26 and were required to extract information from that paper to design an experiment exploring the rate of reaction in the presence and absence of micelles. Typically, this required students to determine the critical micelle concentration and study the reaction in the presence surfactant molecules at low and high concentrations, so that they were below and above the critical micelle concentration.…”

Insights into the binding interaction between copper ferrite nanoparticles and bovine serum albumin: An effect on protein conformation and activity

“…The concentration of BSA stock solution was determined using a molar extinction coefficient (ε) of 43 824 M −1 cm −1 at 280 nm . For spectroscopic studies, a BSA solution (fixed concentration) was mixed with various concentration of CuFe 2 O 4 NP and the protein–nanoparticle mixture was incubated for 2 h to attain binding equilibrium.…”

“…Trp‐134 and 213 are located in the BSA amino acid sequence. Due to its low cost, high stability, availability, water solubility, exceptional ligand binding capability and 80% sequence similarity with human serum albumin (HSA), BSA has been extensively investigated as a model protein in various interaction studies …”