Highly selective molecularly imprinted overoxidized polypyrrole colloids: one-step preparation technique.

A convenient "one step" preparation process of molecularly imprinted overoxidized-polypyrrole (oPPy) colloids by chemical polymerization and their high uptake ability and enantioselectivity are described. Since an oxidizing agent gives a different standard redox potential and rate of polymerization, the property of the resulting oPPy colloid can be controlled by the kind and concentration of the oxidizing agent. At higher concentrations of (NH4)2S2O8 (0.3 M), the overoxidation of PPy colloid automatically occurred. The extraction of L-lactate as a dopant has created a shape-complementary cavity on the surface of the oPPy colloid through overoxidation following polymerization. The oPPy colloid exhibited an excellent selectivity not only on the alanine enantiomer but also on the difference in the side-chain size of amino acids. The uptake of oPPy colloid towards L-alanine over D-alanine was 11.3 micromol/g-colloid against 3.6 micromol/g. The molecularly imprinted cavity can also recognize the existences of the OH or CH3 substituents.     

An Improved Protocol for the Synthesis of 2‐Nitro‐7,8,17,18‐tetrabromo‐5,10,15,20‐tetraphenylporphyrin and its Conformational Aspects by Electrochemistry and Spectroscopy

An improved methodology is reported for the synthesis of 2‐nitro‐7,8,17,18‐tetrabromo‐5,10,15,20‐tetraphenylporphyrin by the β‐mononitration of 2,3,12,13‐tetrabromo‐5,10,15,20‐tetraphenylporphyrin using 50% HNO₃. The copper derivative of this compound showed the expected trend in redox potentials where the free‐base form showed an opposite one on comparing with the corresponding non‐nitro analogs. This opposite trend is ascribed to the role of nitro group in dictating the extent of nonplanarity of the porphyrin as indicated by the electronic and ¹H NMR spectral studies.     

LC-MS/MS Peptide Mapping with Automated Data Processing for Routine Profiling of N-Glycans in Immunoglobulins

Protein N-Glycan analysis is traditionally performed by high pH anion exchange chromatography (HPAEC), reversed phase liquid chromatography (RPLC), or hydrophilic interaction liquid chromatography (HILIC) on fluorescence-labeled glycans enzymatically released from the glycoprotein. These methods require time-consuming sample preparations and do not provide site-specific glycosylation information. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) peptide mapping is frequently used for protein structural characterization and, as a bonus, can potentially provide glycan profile on each individual glycosylation site. In this work, a recently developed glycopeptide fragmentation model was used for automated identification, based on their MS/MS, of N-glycopeptides from proteolytic digestion of monoclonal antibodies (mAbs). Experimental conditions were optimized to achieve accurate profiling of glycoforms. Glycan profiles obtained from LC-MS/MS peptide mapping were compared with those obtained from HPAEC, RPLC, and HILIC analyses of released glycans for several mAb molecules. Accuracy, reproducibility, and linearity of the LC-MS/MS peptide mapping method for glycan profiling were evaluated. The LC-MS/MS peptide mapping method with fully automated data analysis requires less sample preparation, provides site-specific information, and may serve as an alternative method for routine profiling of N-glycans on immunoglobulins as well as other glycoproteins with simple N-glycans.

Synthesis of Potential Impurities of Bicalutamide

Bicalutamide is an oral nonsteroidal, anti-androgen drug used for prostate cancer. It binds to the androgen receptor. During the bulk synthesis of bicalutamide, various impurities are formed. The present work details the development of simple processes for the preparation of impurities of bicalutamide, viz bical-sulfoxides (6), bical-deshydroxy (10), bical-desfluoro (10a), bical-2-fluoro (10b), and bical-3-fluoro (10c).     

Prospective of Microbial Exopolysaccharide for Heavy Metal Exclusion

Metals as a resource are depleting, and on another side, it fetches serious environmental pollution causing a threat to human health and ecosystem. The heavy metal accumulation due to anthropogenic activities results in toxicological manifestation. The traditional methods of remediation are not cost effective, efficient, and ecofriendly which necessitate and motivate towards the safe, effective, and ecofriendly biological methods. The increasing presence of heavy metals in the microbial habitat compels the microbes to develop the ability to tolerate or resist the presence of heavy metals. Exopolysaccharide (EPS) production is one of the strategies of microbes to fight against metal stress. EPS is a microbial biopolymer which is generally produced under stress from harsh environment and nutrition conditions. EPSs are cell-associated or secreted outside the cell and comprised organic macromolecules such as polysaccharides, proteins, and phospholipids in addition to some non-polymeric molecules. EPSs work as competent biosorbents with an anionic reactant group that effectively sequesters cationic heavy metals by electrostatic interactions. The present paper summarizes the EPSs with its types, role, and biosynthesis and an endeavor to elucidate the interaction mechanism of EPSs with heavy metal with supportive and distinctive applications for heavy metal exclusion. The review concluded with the current challenges and future prospects to make the EPS an efficient biosorbent.     

Chemical‐Bath‐Deposited Indium Oxide Microcubes for Solar Water Splitting

We fabricated films of cubic indium oxide (In₂O₃) by chemical bath deposition (CBD) for solar water splitting. The fabricated films were characterized by X‐ray diffraction analysis, Raman scattering, X‐ray photoelectron spectroscopy, and scanning electron microscopy, and the three‐dimensional microstructure of the In₂O₃ cubes was elucidated. The CBD deposition time was varied, to study its effect on the growth of the In₂O₃ microcubes. The optimal deposition time was determined to be 24 h, and the corresponding film exhibited a photocurrent density of 0.55 mA cm^?2. Finally, the film stability was tested by illuminating the films with light from an AM 1.5 filter with an intensity of 100 mW cm^?2.     

Unprecedented "In Water" imidazole carbonylation: paradigm shift for preparation of urea and carbamate

The first "In Water" imidazolecarbonylation of amine is described. A one pot reaction of carbonylimidazolide in water with a nucleophile provides an efficient and general method for the preparation of urea, carbamates and thiocarbamates. Use of an anhydrous solvent and an inert atmosphere could be avoided. Product precipitate out from the reaction mixture and can be obtained in high purity by filtration, resulting in a simple and scalable method.     

Thin Layer Chromatography of Purines on Silica Gel G Impregnated with Transition Metal Ions; Assay of Caffeine and Theophylline in Pharmaceutical Formulations

This study was undertaken to develop thin layers of silica gel G impregnated with transition metal ions for separation, identification and estimation of purines. The influence of transition metal ions and eluting solvents on chromatographic behaviour (hR_f) has been studied. The method was applied for qualitative analysis of purines in the mixtures and quantitative analysis of purine bases in the mixture as well as in pharmaceutical formulations. The results were compared statistically with those obtained by official methods. The method is simple, reproducible, and accurate within 1.3 ± 0.6%.     

A switchable self-doped polyaniline: interconversion between self-doped and non-self-doped forms

A novel strategy for the synthesis of a substituted polyaniline that can be switched between a self-doped and non-self-doped state is presented. The approach uses the complexation between boronic acid-substituted aniline, a diol (d-fructose), and fluoride to generate an anionic monomer. Under these conditions, chemical polymerization results in a self-doped, water-soluble, conducting polyaniline under neutral aqueous conditions. The self-doped polymer can be simply and reversibly converted to an insoluble non-self-doped form by reducing the concentration of fluoride. Characteristics of the polymerization reaction and the resulting polymer are discussed.     

Pulsed amperometric detection of underivatized amino acids using polypyrrole modified copper electrode in acidic solution

The successful pulsed amperometric detection of underivatized amino acids have been carried out in an acidic media on a polypyrrole (PPy) modified Cu electrode. The formation of PPy film doped with glutamate (glu) on a Cu electrode surface changes the mechanism of Cu dissolution. After application of multistep potential waveform, the PPy film was glu free due to the electro-reduction and overoxidation. High anodic potential polarization treatment yielded partially overoxidized PPy film as long as the Cu surface dissolution and amino acid permeation through the film was well controlled. This overoxidized PPy film acted as a charge and size exclusion barrier in order to improve the selectivity and stability of a Cu electrode. Various process parameters such as film modification time, detection and cleaning potential and pH of solution have been optimized to maximize the beneficial electrocatalytic properties of the electrode surface. At an optimized condition, detection limits for positively charged histidine and arginine are 19 and 22 pg respectively, whereas the neutral amino acids detected in amounts of 0.9–2.3 ng. Furthermore, the PPy coated Cu electrode response was long lived, stable and reproducible.