ABSTRACT
The presence of saccharin (SH) could be efficiently sensed (in the concentration range of 5 × 10-5 M to 5 × 10-1 M) through the interference synthesis of gum ghatti (GG) capped silver nanoparticles (GGAgNps). The synthesis used sodium borohydride and gum ghatti (GG) as the reducing and capping agents respectively. The strong hydrogen-bonding recognition between GG and SH was responsible for the interference. The intensity of the SPR peak of GGAgNps was found linearly dependent on [SH]. The SH detection was further enhanced when combo capping comprising of GG and chitosan (Ch) (in 1:1 weight ratio) was used while the use of gum acacia (GA) in place of Ch (in combo) decreased the detection sensitivity. The combo polysaccharide solutions had non-Newtonian behaviour and shear thinning property like GG. The method was also applied for the successful detection of SH in commercially available real juice samples.
Subject(s)
Metal Nanoparticles/chemistry , Plant Gums/chemistry , Saccharin/analysis , Silver/chemistry , Borohydrides/chemistry , Hydrogen-Ion Concentration , Metal Nanoparticles/ultrastructure , Particle Size , Polysaccharides/chemistry , Silver Nitrate/chemistry , Spectrophotometry, Ultraviolet , Spectroscopy, Fourier Transform Infrared , Static Electricity , Sweetening Agents/analysis , Time Factors , ViscosityABSTRACT
An excellent catalyst (GNiOc) for reduction of nitroarenes with sodium borohydride is being reported. The synthesis of GNiOc was carried out by direct precipitation method using guar gum (GG) as the modifier. The nanostructures have been characterized using UV-visible spectroscopy (UV-vis), Fourier transformation infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) surface area analysis, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and Thermal (TGA and DTA) analysis. TEM analysis revealed that GNiOc sample is crystalline in nature (similar to cubic NiO) and had an average particle size of ~3â¯nm. The reduction of 4nitrophenol (4NP) (2â¯mM) using sodium borohydride (0.1â¯M) was completed within 2â¯min when GNiOc (5â¯mg) was used as catalyst. GNiOc could be successfully recovered and reused for six repetitive cycles and even in the sixth cycle; the reduction was completed in 18â¯min time. The reduction followed zero order kinetics, the rate constant being 8â¯×â¯10-3â¯mmolâ¯L-1â¯min.-1 Under identical experimental conditions, GNiOc catalyzed reductions (with sodium borohydride) of 4nitroaniline (4NA) and 4nitro benzoic acid (4NBA) were completed in 6 and 7â¯min respectively, while NiO required >15â¯min time for reducing all the three nitroarenes.
Subject(s)
Borohydrides/chemistry , Galactans/chemistry , Mannans/chemistry , Nanoparticles/chemistry , Nickel/chemistry , Nitrophenols/chemistry , Plant Gums/chemistry , 4-Aminobenzoic Acid/chemistry , Catalysis , Oxidation-Reduction , Phenylenediamines/chemistryABSTRACT
Aloevera (AV) polysaccharide/acrylonitrile (AN) nanoparticles (AVANp4 of â¼50nm size) have been crafted via free radical polymerization method using persulfate/ascorbic acid (KPS/AA) and methylenebisacrylamide (MBA) as the redox initiator and crosslinker respectively. AVANp4 was extensively characterized using FTIR, SEM, TEM, XRD, and Thermal analysis (TGA & DTG). Inclusion of AN in AV polysaccharide has been evidenced by nitrile stretching peak at 2244cm-1 in FTIR spectrum of AVANp4. Colon specific targeted in-vitro release of 5-Aminosalicylic acid from AVANp4 has been studied in pH 1.2 and pH 7.4 buffer solutions at 37°C. The controlled release was witnessed up to 48h for AVANp4 in contrast to AV for which the release exhausted within 7-8h in both the buffers. The delayed release of the drug from AVANp4 is attractive since it can allow the drug to reach colon rather than being released in the upper part of the gastrointestinal tract.
