Abstract Stoichiometric ionization constants of some pyrazole carboxylic acids [4-benzoyl-1-(3-nitrophenyl)-5-phenyl-1H-pyrazole-3-carboxylic
acid, 4-benzoyl-1-(4-nitrophenyl)-5-phenyl-1H-pyrazole-3-carboxylic acid, 4-(ethoxycarbonyl)-1,5-diphenyl-1H-pyrazole-3-carboxylic
acid, 4-(ethoxycarbonyl)-1-(3-nitrophenyl)-5-phenyl-1H-pyrazole-3-carboxylic acid, 4-(ethoxycarbonyl)-1-(4-nitrophenyl)-5-phenyl-1H-pyrazole-3-carboxylic
acid] were determined in ethanol–water mixtures of 50, 60, 70% ethanol (v/v) by a potentiometric titration method. Titrations
were performed in an ionic strength of 0.10 M NaCl at 25.0 ± 0.1 °C using an Orion 960 automatic titrator under a nitrogen
atmosphere. Using the potentiometric titration data, ionization constants were calculated in three different ways. The effects
of structure and solvent on the acidity of pyrazole carboxylic acids are also discussed.
Graphical abstract
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Solid-phase extraction (SPE) based on molecularly imprinted polymers (MIPs) were used to develop selective separation and preconcentration for methylmercury ion from complex matrixes. In this study, an ion-imprinting polymer was prepared to make artificial organomercury lyase preorganizing three methacryloyl-(l)-cysteine methylester (MAC) monomers and one methylmercury ion in a three-coordinate form by template polymerization, with the goal preparing a solid-phase which has the high selectivity for methylmercury ions.Methylmercury-imprinted beads were produced by a dispersion polymerization technique with use methylmercury-methacryloyl-(l)-cysteine (MM-MAC) complex monomer and ethylene glycoldimethacrylate (EDMA). After removal of methylmercury ions, methylmercury-imprinted beads were used for solid-phase extraction and determination of mercury compounds. Methylmercury adsorption and selectivity studies of methylmercury versus other metal ions which Hg(II), Zn(II), Pb(II) and Cd(II) were reported and distribution and selectivity coefficients of these ions with respect to methylmercury were calculated here.ICP-OES and HPLC-DAD determinations of methylmercury and mercury ions in the certified reference, LUTS-1 from the National Research Council of Canada and synthetic sea water showed that the interfering matrix had been almost removed during preconcentration. The methylmercury-imprinted solid-phase as mimic receptor was good enough for methylmercury determination in complex matrixes. 相似文献
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