Deactivation of Sn-Beta zeolites caused by structural transformation of hydrophobic to hydrophilic micropores during aqueous-phase glucose isomerization

Spectroscopic, titration and kinetic methods were used to probe the deactivation of Sn-Beta in water.

A 4-(1H-Benzo[d]oxazole-2-yl)-2-methoxyphenol as Dual Selective Sensor for Cyanide Ion Detection

A dual sensor based on benzoxazole containing moiety S3 was successfully synthesized and applied for detection of CN− ion. The S3 molecule changed its colour for dark brown to dark green on addition of the CN− ion only in DMSO solvent. The limit of detection (LOD) and association constant (Kass) values was 0.4 × 10−6 M and 1.0 × 107 M−1; and 0.46 × 10−4 M and 1.0 × 105 M−1 determined by UV-visible spectroscopic titration and fluorescence titration, respectively.

Characterization of Co(II)-PAMAM dendrimer complexes with polypropylene oxide core by using UV-VIS spectroscopy

<p>The aim of this study was to characterize poly(amidoamine) (PAMAM) dendrimer complexes of Co(II) ions by using UV-Vis spectroscopy. For this aim, a generation-4 polypropylene oxide (Jeffamine^® T-403) cored and amine-terminated PAMAM dendrimer (P₄) was used as a model complexation agent. Optimum complexation condition for P₄ was determined by potentiometric and spectroscopic titration studies. Extent of protonation (EOP) of the amino groups of P₄ was determined from the potentiometric titration data and validated with spectroscopic titration data. The results indicated that pH 8 was the optimum dendrimer aqueous solution media, where the available number of tertiary amines present in P₄was the highest for possible metal complexation. At the optimized conditions, UV-Vis characterization of the Co(II)-P₄ complexes was performed and 585–635 nm <em>d-d</em> transition bands were observed as the characteristic complexation bands of the tertiary amine groups of P₄ with Co(II) ions. Obtained Co(II)-P₄ complexes might be considered for the development of magnetic resonance image (MRI) improvers or MRI contrast agents.</p><p class="Abstract"><span lang="EN-US"><br /></span></p>

Interaction of europium and curium with alpha-amylase

Batch sorption experiments, potentiometric and spectroscopic titration investigations revealed a fast and strong interaction of Eu(iii) and Cm(iii) with the digestive enzyme α-amylase.