Anodic stripping voltammetry of arsenic determination with edible mushroom-nafion-modified glassy carbon electrode.

An edible Mushroom-Nafion modified glassy carbon electrode (MN-GCE) was prepared using a homogeneous mixture varying the concentrations of these, in addition to the origin of the mushroom (Shiitake, Lentinula edodes, M and Abrantes, Agariscus bisporus, M) and applied to the As(III) determination by anodic stripping voltammetry. After choosing the optimal conditions in the preparation of the electrode, the second stage was to study the effects of various parameters such as supporting electrolyte, pH, accumulation potential, and time (E, t). The optimum experimental conditions chosen were Britton Robinson buffer 0.

Application of Switchable Hydrophobicity Solvents for Extraction of Emerging Contaminants in Wastewater Samples.

In the present work, the effectiveness of switchable hydrophobicity solvents (SHSs) as extraction solvent (,-Dimethylcyclohexylamine (DMCA), ,-Diethylethanamine (TEA), and ,-Benzyldimethylamine (DMBA)) for a variety of emerging pollutants was evaluated. Different pharmaceutical products (nonsteroidal anti-inflammatory drugs (NSAIDs), hormones, and triclosan) were selected as target analytes, covering a range of hydrophobicity (LogP) of 3.1 to 5.

Gold nanoparticles as an efficient drug delivery system for GLP-1 peptides.

In this work, the potential application of gold nanoparticles for GLP-1 analogues delivery was studied. For this purpose, the original sequence of the incretin GLP-1 was slightly modified in the C-terminal region by adding a cysteine residue to facilitate conjugation to the gold surface. The interaction between peptides and gold nanoparticles and also the colloid stability of the conjugates were studied by UV-vis spectrophotometry, TEM, IR and XPS spectroscopy.

Heterologous expression of an α-amylase inhibitor from common bean (Phaseolus vulgaris) in Kluyveromyces lactis and Saccharomyces cerevisiae.

Background: Phaseolamin or α-amylase inhibitor 1 (αAI) is a glycoprotein from common beans (Phaseolus vulgaris L.) that inhibits some insect and mammalian α-amylases. Several clinical studies support the beneficial use of bean αAI for control of diabetes and obesity.

Hantzsch dihydropyridines: Privileged structures for the formation of well-defined gold nanostars.

Anisotropic and branched gold nanoparticles have great potential in optical, chemical and biomedical applications. However their syntheses involve multi-step protocols and the use of cytotoxic agents. Here, we report a novel one-step method for the preparation of gold nanostructures using only Hantzsch 1,4-dihydropyridines as mild reducing agents.

Ionic liquids for improving the extraction of NSAIDs in water samples using dispersive liquid-liquid microextraction by high performance liquid chromatography-diode array-fluorescence detection.

A rapid, sensitive and efficient analytical method based on the use of ionic liquids for determination of non-steroidal anti-inflammatory drugs (NSAIDs) in water samples was developed. High-performance liquid chromatography equipped with a diode array and fluorescence detector was used for quantification of ketoprofen, ibuprofen and diclofenac in tap and river water samples. This new method relies on the use of two ionic liquids with multiple functionalities: one functions as an extraction solvent (1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), and the other changes the polarity in the aqueous medium (1-butyl-3-methylimidazolium tetrafluoroborate, ([BMIM][BF4]).

Stability and drug metabolism assessed by electrochemical methods.

This review is focused on the use of the electrochemical techniques, voltammetry and polarography, as well as biosensors, for the study of drug stability. In addition, this review also details the study of drug metabolism by electrochemistry and mass spectrometry. This is used as a tool to mimic drug metabolism and because it is a purely instrumental method, may have advantages over, or be complementary to, the existing biological assays.

Electrochemistry of interaction of 2-(2-nitrophenyl)-benzimidazole derivatives with DNA.

In this study the interaction between new benzimidazole molecules, 2-(2-nitrophenyl)-1H-benzimidazole (NB) and N-benzoyl-2-(2-nitrophenyl)-benzimidazole (BNB), with dsDNA and ssDNA was assessed at pH 7.4. Using differential pulse voltammetry at glassy carbon electrode, both molecules were electrochemically reduced due to the presence of a nitro group in their structures.

Determination and characterization of new benzimidazoles with activity against Trypanosoma cruzi by UV spectroscopy and HPLC.

This work presents the development of analytical methodologies by UV spectrophotometry and HPLC to characterize five nitroarylbenzimidazole derivatives with activity against Trypanosoma cruzi: NB, BNB, PNB, PMNB and PCNB. Both methodologies exhibit adequate repeatabilities and reproducibilities (CV<2%) and recoveries higher than 98%. The ionization constants (pK(a)), lipophilicity (log P) and effective permeability (Pe) are reported.

How changes in the sequence of the peptide CLPFFD-NH2 can modify the conjugation and stability of gold nanoparticles and their affinity for beta-amyloid fibrils.

In a previous work, we studied the interaction of beta-amyloid fibrils (Abeta) with gold nanoparticles (AuNP) conjugated with the peptide CLPFFD-NH2. Here, we studied the effect of changing the residue sequence of the peptide CLPFFD-NH2 on the efficiency of conjugation to AuNP, the stability of the conjugates, and the affinity of the conjugates to the Abeta fibrils. We conjugated the AuNP with CLPFFD-NH 2 isomeric peptides (CDLPFF-NH2 and CLPDFF-NH2) and characterized the resulting conjugates with different techniques including UV-Vis, TEM, EELS, XPS, analysis of amino acids, agarose gel electrophoresis, and CD.

In vitro interaction between homocysteine and copper ions: Potential redox implications.

Homocysteine (Hcys) has been implicated in various oxidative stress-related disorders. The presence of a thiol on its structure allows Hcys to exert a double-edge redox action. Depending on whether Cu2+ ions occur concomitantly, Hcys can either promote or prevent free radical generation and its consequences.

Stability study of simvastatin under hydrolytic conditions assessed by liquid chromatography.

In this work, a liquid chromatography stability-indicating method was developed and applied to study the hydrolytic behavior of simvastatin in different pH values and temperatures. The selected chromatographic conditions were a C18 column; acetonitrile-28 mM phosphate buffer solution, pH 4 (65 + 35) as the mobile phase; 251 degrees C column temperature; and flow rate 1 mL/min. The developed method exhibited an adequate repeatability and reproducibility (coefficient of variation 0.

Voltammetric behavior of zaleplon and its differential pulse polarographic determination in capsules.

In this work both the electrochemical behavior and the analysis of the hypnotic pyrazolopyrimidine derivative zaleplon were studied. Zaleplon in ethanol-0.1M Britton Robinson buffer solution (30-70) showed 2 irreversible, well-defined cathodic responses in the pH range of 2-12 using differential pulse polarography (DPP), tast polarography, and cyclic voltammetry.

Differential pulse voltammetric assay of lercanidipine in tablets.

Lercanidipine in ethanol-0.04M Britton-Robinson buffer (20 + 80) gives an irreversible anodic response on a glassy carbon electrode in a broad pH range (2-12) that depends on pH. This signal can be attributed to oxidation of the 1,4-dihydropyridine ring to give the corresponding pyridine derivative.