Voltammetric Study and Rapid Quantification of Resorcinol in Hair Dye and Biological Samples Using Ultrasensitive Maghemite/MWCNT Modified Carbon Paste Electrode

Increased concern over the risk resorcinol (RS) pose to ecology and humans, led to its position in European Union Category 1 list of endocrine disruptors. Legal measures restricted RS utilization and hence crucial to monitor its levels in the environment. Herein we report development of highly efficient and economically viable electrochemical sensor for quantitative determination of RS based on 77Maghemite/MultiWall Carbon Nanotube (M/MWCNT) modified carbon paste electrode. M/MWCNT was synthesized via strategic IR irradiation for the first time, a promising approach to overcome other complicated chemical routes. Powder X‐ray diffraction (PXRD), Transmission electron microscopy (TEM), Field emission scanning electron microscopy (FESEM) and Energy dispersive X‐ray (EDX) were used for characterization. Using Differential Pulse Voltammetry (DPV), we report the lowest detection limit at 0.02 μM. The potential application of the sensor was accomplished as a result of excellent recoveries made from real samples fortified with RS. Results indicated the proficiency of the sensor reliable for rapid, onsite monitoring of RS water contamination and in biological matrices.     

Gradient elution isotachophoresis with direct ultraviolet absorption detection for sensitive amino acid analysis

This work demonstrates coupling of the newly described electrophoretic enrichment technique of gradient elution isotachophoresis (GEITP) to a low-cost, conventional ultraviolet absorbance detector to realize sensitive measurements with a universal detector, eliminating the need for fluorescent analytes or derivatization. The effects of various parameters on enrichment were studied, including current density varied by leading electrolyte concentration, current density varied by applied electric field, and counter-flow acceleration across varying capillary inner diameters. Optimized parameters were applied to the enrichment and separation of the amino acids tryptophan (Trp) and tyrosine (Tyr). Limits of detection for Trp and Tyr were 51 and 215 nM, respectively, reflecting sensitivity enhancements of 860- and 1900-fold. Analysis times were less than 6 min, and peak height RSDs were less than 4%. A demonstration of enrichment and separation of these amino acids from artificial cerebrospinal fluid is additionally shown as a first step to realizing biochemical monitoring by GEITP.     

Synthesis,spectroscopic characterization and in vitro antitumor activities of some novel mononuclear Ru(Ⅱ) complexes

The synthesis and spectroscopic characterization of ruthenium complexes（R-l to R-8） of the type[Ru（A）₂（B）],(where A = 1,10-phenanthroline/2,2′-bipyridine and B = 3.4.5-tri-OCH₃DPC,4-CH₃-DPC,4-N-（CH₃）₂-DPC,4-NO₂-DPC arc described. These ligands form bidentate octahedral ruthenium complexes.The title complexes were subjected to in vitro cytotoxic activity measurements against the human cancer T-lymphocyte cell lines MTT assay.In vitro evaluation of these ruthenium complexes revealed cytotoxic activity from 0.24 to 1.4μg/mL against CEM,0.44 to 1.9μg/mL against Molt4/C8.0.28 to 1.5μg/mL against L1210,0.24 to 0.98μg/mL against HL60,and 0.25 to 1.2μg/mL against BEL7402,depending the nature of the compound.     

Stereoselective total synthesis of Patulolide C

Abstract

Stereoselective total synthesis of Patulolide C has been accomplished from easily available and inexpensive (S)-chiral epoxide. The key steps involved in the concise synthesis of Patulolide C utilizes ring opening of chiral epoxide, cleavage of 1,2-diol, deprotection of benzyl ether of hydroxyl acid and Yamaguchi macrolactonisation dilution conditions as key steps. The advantage of this method include inexpensive starting material, mild reaction conditions and high purity of products.     

Thio‐bromo “Click,” post‐polymerization strategy for functionalizing ring opening metathesis polymerization (ROMP)‐derived materials

The use of a thio‐bromo click strategy as an efficient postpolymerization tool is described. Norbornene derivatives bearing an α‐bromo ester could be polymerized using Grubbs 2^nd generation initiator to provide α‐bromo ester‐containing homo‐and block copolymers that could be efficiently functionalized through reactions with various thiols. A one‐pot strategy was also used, in which up to four different thiols were reacted simultaneously. This chemistry could also be used as an efficient cross‐linking strategy to form ROMP‐based gels as well as a tool for terminal functionalization of polypropylene‐based oligomers. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 179–185     

Oxidovanadium (IV) and iron (III) complexes with O2N2 donor linkage as plausible antidiabetic candidates: Synthesis,structural characterizations,glucose uptake and model biological media studies

With the upsurging cases of type II diabetic patients, the demand for safe and effective oral antidiabetic drugs is also increasing. Coordination complexes have proven their mettle as efficient oral drug candidates, which thereby motivated us in this work to design new transition metal complexes as plausible candidates for the treatment of diabetes. A reduced salen ligand, {H₂(hpdbal)₂-an} ( 1 ) derived vanadium (IV) and iron (III) complexes, namely, [V^IVO{(hpdbal)₂-an}] ( 2 ) and [{Fe^III (OH₂)((hpdbal)₂-an)}₂ μ₂-SO₄] ( 3 ) were synthesized in this study. The newly obtained ligand and complexes were characterized using usual analytical and spectroscopic techniques. The potential of these compounds in inducing increased glucose uptake by diabetic cells were studied by using insulin resistant HepG2 cells as model diabetic cells and 2-NBDG molecule as a D-glucose analogue and fluorescent tracker. The cells added with the vanadium (IV) complex 3 induced significant NBDG uptake of 95.4% which was higher than that induced by metformin, the standard antidiabetic drug. To elucidate the behavior of the complexes in biological media, model solution studies were conducted with a wide range of pH conditions and protein bovine serum albumin (BSA). The complexes demonstrated effective binding with BSA which was concluded through spectroscopic titration studies and were also found to be sufficiently stable over physiological pH conditions. The study can thus prove to be beneficial in the quest for new antidiabetic drugs.     

Pd/ligand-free synthesis of thienopyranones via Cu-catalyzed coupling-cyclization in PEG 400 under ultrasound

A greener and practical synthesis of 5-substituted thieno[2,3-c]pyran-7-ones has been achieved via Cu-catalyzed coupling-cyclization of 3-iodothiophene-2-carboxylic acid with terminal alkynes in the presence of K₂CO₃ in PEG 400 under ultrasound irradiation. A range of thienopyranone derivatives were synthesized by using this inexpensive and Pd- and ligand-free methodology.     

MWCNT/Nileblue Heterostructured Composite Electrode for Flavanone Naringenin Quantification in Fruit Juices

Naringenin (NR) displays strong antioxidant and numerous pharmacological activities, mitigating severity of metabolic‐syndromes without undesirable side‐effects. With the upsurge of interest in administering NR as diet‐supplement antioxidant, in this work for the first time we implemented functionalized‐MWCNT/Nileblue‐composite on carbon paste electrode (fMWNCT/NB/MCPE), as electrochemical sensor for catalytic NR oxidation. Integrated properties of fMWCNT/NB and their consonance with CPE, led to lowering of R_ct value with fast‐kinetics and diminution of over‐potential. NR determination was due to electrical‐conductivity, π‐π and electrostatic‐forces that magnified anodic current by 5.5 fold. In the pH range 3.0 to 10.0 NR undergoes irreversible oxidation via transfer of 1e^?/H⁺. Critical parameters, namely, pH and scan rate were assessed to reinforce differential pulse voltammtery (DPV) sensitivity for quantitative measurements. Sensor's selectivity, stability, accuracy and reproducibility were determined. Finally its viability in quantifying NR was validated by scrutinizing NR fortified fruit juices, as real sample matrices.