Chemical Oxidative Synthesis and Characterization of Poly(8-hydroxyquinoline) Particles

Facile extraction and determination of organophosphorus pesticides using poly (8-hydroxyquinoline) functionalized magnetic multi-walled carbon nanotubes nanocomposite in water, fruits, and vegetables samples

This study presents a dispersive micro-solid phase extraction (D-μ-SPE) approach for extracting and determining of two organophosphorus pesticides (OPPs), including diazinon and chlorpyrifos as model analytes in various samples. For this purpose, we synthesized, characterized, and utilized magnetic multi-walled carbon nanotubes coated with poly 8-hydroxyquinoline (MWCNTs/Fe3O4@PHQ) as a novel sorbent. The impact of various parameters, including sorbent type, sample pH, sample volume, sorbent amount, desorption solvent (type and volume), extraction time, and ionic strength on the extraction efficiency was investigated and optimized. Following the extraction, the desorbed pesticides in acetone were analyzed using gas chromatography with an FID detector. Under the optimized experimental conditions, the proposed method showed excellent linearity in the range of 3-1000 µg/L, low detection limit (0.9-1.5 µg/L), good relative recoveries (86-101.5 %), and high precision (RSD < 6.5 %). Finally, the applicability of this method was evaluated by analyzing the target OPPs in a variety of real samples, and obtained satisfactory results.

Enzymatic synthesis of 5-amino quinoline oligomers and evaluation of their free radical scavenging activity

The compound 5-aminoquinoline (AQ) was treated with horseradish peroxidase (HRP) and H2O2 in a reaction medium containing a dioxane:phosphate buffer mixture (70:30). Products (OAQ) with a degree of polymerization ranging from 4 to 12 were obtained. 1H NMR, FTIR, UV–vis, SEM, TG–DTA, DSC, XRD analysis, and conductivity measurements were conducted for characterization of OAQ. Compared with a monomer, OAQ showed higher thermal stability. After heating to 1000 °C, 46% of the initial weight of the OAQ remained. The antioxidant efficiencies of the monomer and oligomer were evaluated by the typical spectrophotometric method such as the bleaching of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. OAQ showed improved DPPH activity compared with the AQ monomer.

Regioselective synthesis of polygamma (γ) acid

The oxidative polymerization of 6-amino-4-hydroxy-2-naphthalenesulfonic acid was carried out in an aqueous alkaline medium. The polymer showed uncommon multicolored emission behavior in DMSO, emitting blue, green, and yellow light at 405, 480, and 532 nm, respectively.