A novel cellulose-based resin functionalized with polyallylamine was synthesized. It was applied to the collection of phosphate in environmental water samples, followed by concentration determination using an inductively coupled plasma-atomic emission spectrometer (ICP/AES). The synthesized resin, cellulose-glycidylmethacrylate-polyallylamine (CGP), showed good adsorption behavior toward trace amounts of phosphate over a wide pH range. The adsorbed-analyte can be easily eluted using 0.5 M hydrochloric acid; its recoveries was found to be 80 -100%. The CGP resin synthesized was packed in a mini-column, which was then installed in a computer-controlled auto-pretreatment system for on-line collection/concentration and determination of trace phosphate by ICP/AES. The limit of detection for phosphate was found to be 0.6 μg P l -1 . The sample volumes were only 5 ml and the total analysis time was about 4 min. The developed method with CGP resin was successfully applied to the determination of phosphate in river water and tap water samples with satisfactory results. The recovery test showed that common matrices that may exist in environmental waters did not interfere with the determination of phosphate.
A stable phenoxy1 derivative (1) of benzo-15-crown-5 (B15C5) has been prepared and the complex formation between the spin-labeled crown ether 1 and the alkali (Li+, Na+, K+, and Rb+) and alkaline-earth (Mg2+, Ca2+, Sr2+, and Ba2+) metal salts has been studied by the ESR technique. The result of the ESR observations has established the new fact that two kinds of 2:l complexes having different structures and a 1:l complex coexist at equilibrium in all the ethanol solutions of 1 containing the above metal salts. Structural information for the two kinds of 2:l complexes was deduced from detailed analysis of the observed triplet ESR spectra and the calculation of the zero-field splitting (zfs) parameters.
IntroductionThe preparation and properties of a number of cyclic polyethers have been previously reported by Pedersen.1,2 It was shown that certain of these polyethers form stable complexes with alkali and alkaline-earth metal cations. Many investigations of the positive ion effect for the complex formation in solution and in the solid state have been r e p~r t e d .~ The stoichiometry of the crystalline
Environment dependence of the selectivity in oxidation of a pair of associating thiols was examined in binary solvent mixtures of an alcohol or acetonitrile with water and an organic cosolvent. The discrimination between the two nonpolar groups (n- and i-C5H11 groups, phenyl and p-tolyl groups, or n- and i-C4H9 groups) of one of the thiols was found to occur more specifically in aqueous media than in the corresponding nonaqueous media.
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