Kinetic catalytic determination of trace levels of iodide based on the oxidation of basic dyes with hydrogen peroxide monitored potentiometrically using simple PVC electrodes

Four sensitive catalytic potentiometric methods have been developed for trace levels determination of iodide based on its catalytic effects on the oxidation of four dyes: viz. variamine blue (VB), rhodamine B (RB), methylene blue (MB) and malachite green (MG), with H₂O₂ in H₃PO₄ medium at 25 ± 0.5 °C. The catalyzed reaction rates were estimated potentiometrically by monitoring the potential of the corresponding dye-PVC ion selective electrodes. To select the optimized reaction conditions offering the highest sensitivity of the method, parallel studies were carried out on each dye catalyzed reaction including: the effect of reactant concentration, reaction medium and temperature. The working calibration curves were linear over the concentration range from 0.32 to 2.54 mg L⁻¹ iodide for VB method and from 3.2 to 12.7 mg L⁻¹ for other ones. The tolerance limits of more than 20 interfering species were listed indicating the high selectivity of the method. Trace iodide in edible salt and pharmaceutical samples was determined without the need for separation or preconcentration procedures.     

A new tetrapyrazolic macrocycle. Synthesis and its use in extraction and transport of K, Na and Li

The synthesis of a new tetrapyrazolic macrocyclic structure with a functionalised arm is described. The complexing properties of this new compound towards alkali metal ions (K⁺, Na⁺, Li⁺) were studied by liquid-liquid extraction and liquid membrane transport processes. The extracted and the transport cation percentage were determined by atomic absorption measurements and UV spectroscopy.     

Monoclonal Antibodies Application in Lateral Flow Immunochromatographic Assays for Drugs of Abuse Detection

Lateral flow assays (lateral flow immunoassays and nucleic acid lateral flow assays) have experienced a great boom in a wide variety of early diagnostic and screening applications. As opposed to conventional examinations (High Performance Liquid Chromatography, Polymerase Chain Reaction, Gas chromatography-Mass Spectrometry, etc.), they obtain the results of a sample’s analysis within a short period. In resource-limited areas, these tests must be simple, reliable, and inexpensive. In this review, we outline the production process of antibodies against drugs of abuse (such as heroin, amphetamine, benzodiazepines, cannabis, etc.), used in lateral flow immunoassays as revelation or detection molecules, with a focus on the components, the principles, the formats, and the mechanisms of reaction of these assays. Further, we report the monoclonal antibody advantages over the polyclonal ones used against drugs of abuse. The perspective on aptamer use for lateral flow assay development was also discussed as a possible alternative to antibodies in view of improving the limit of detection, sensitivity, and specificity of lateral flow assays.     

Anticancer effect of three pyrazole derivatives

The evaluation of the cytotoxic properties in vitro of three synthetic tripods containing pyrazole: N,N-bis[(3,5-dimethylpyrazol-1-yl)methyl]aniline (1); N,N-tetrakis[(3,5-dimethylpyrazol-1-yl)methyl]-para-phenylenediamine (2); and N,N-tetrakis-[(1,5-dimethylpyrazol-3-yl)methyl]-para-phenylenediamine (3), was examined for their cytotoxic activity on two tumor cell lines: P815 (murin mastocytoma) and Hep (human laryngeal carcinome). While the compound 2 shows a small cytotoxic activity, compounds 1 and 3 are more cytotoxic against both cell lines. However, this cytotoxicity is more pronounced against Hep cell line (IC50: 3.25 microg mL(-1) for compound 1 and 6.92 microg mL(-1) for compound 3) than P815 cell line (IC50: 17.82 microg mL(-1) for compound 1 and 37.21 microg mL(-1) for compound 3). Statistical analysis shows that the compound 1 is two- to threefold more cytotoxic than compound 3 (P < 0.05). Interestingly, the cytotoxicity induced by compound 1 against Hep cell line is more important than that induced by adriamycin used as a positive control.     

Effect of two isomeric tetrapyrazolyl ligands on the catalytic oxidation of 3,5-di-tert-butylcatechol

Copper(II) salts were combined with a tetrapyrazolyl ligand ({N,N,N’,N’-tetrakis-[(3,5-dimethylpyrazol-1-yl)methyl)-1,4-phenylenediamine}L1 or {N,N,N’,N’-tetrakis-[(1,5-dimethylpyrazol-3-yl)methyl)-1,4-phenylenediamine}L2) and assessed as oxidation catalysts. The corresponding dioxygen complexes were generated in situ by mixing the copper salt and the pyrazolyl donor ligand in air. The oxidation of 3,5-di-tert-butylcatechol (DTBC), which affords 3,5-di-tert-butylquinone (DTBQ), was studied. The reaction rate was found to depend essentially on the nature of the junction linking two pyrazolyl neighbours.     

New pyrazolic compounds as cytotoxic agents

The evaluation of the in vitro cytotoxic properties of two pyrazole compounds: 1-(4-nitrophényl)-3,5-diméthylpyrazole (1) and 1,1'-di(4-nitrophényl)-5,5'-diisopropyl-3,3'-bipyrazole (2) was investigated against Hep cell line (Human laryngeal carcinoma). These two compounds showed an important cytotoxic activity on the Hep cell line, with IC(50): 8.25 microg mL(-1) for the compound 1; IC(50): 10.20 microg mL(-1) for the compound 2 while the IC(50) for adriamycine used as positive control was 3.62 microg mL(-1).