Sustainable aerogels based on biobased poly (itaconic acid) for adsorption of cationic dyes.

This work reports the synthesis of poly (itaconic acid) by thermal polymerization mediated by 2,2'-Azobis(2-methylpropionamidine) dihydrochloride. Furthermore, physical hydrogels were prepared by using high molecular weight poly (itaconic acid) characterized by low dispersity and laponite RD. The hydrogels presented porous 3D network structures, with a high-water penetration of almost 2000 g/g of swelling ratio, which can allow the adsorption sites of both poly (itaconic acid) and laponite RD to be easily exposed and facilitate the adsorption of dyes. The water adsorption followed Schott's pseudo-second-order model. The mechanism of the adsorption process was investigated using 1H and 31P NMR. The hydrogel is able to fast adsorb by a combination of electrostatic interactions and hydrogen bonding by the synergic effect of the clay and poly (itaconic acid). Moreover, the prepared aerogels exhibited a fast removal of Basic Fuchsin, with an adsorption capacity of 67.56 mg/g and a high removal efficiency (~99 %). The adsorption followed the pseudo-second-order kinetic model and Langmuir isotherm model. Furthermore, the thermodynamic parameters showed that the BF process of adsorption was spontaneous and feasible, endothermic, and followed physisorption. These results indicated that the PIA/laponite-based aerogel can be considered a promising adsorbent material in textile wastewater treatment.

MALDI-ToF mass spectrometry detection of intramolecular composition gradient in copolymers.

Since their addition to the polymer-architecture portfolio, gradient copolymers have attracted significant attention. Up to now, however, the existence of the intramolecular composition gradient must have been ascertained by sampling during living copolymerization because a reliable method for the detection of the composition gradient in the finalized copolymer had not been established yet. Here we show that MALDI-ToF mass spectrometry not only identifies imperfect, i.e. prematurely terminated copolymers but these copolymers can be used as "time capsules" which provide information on composition evolution and the intramolecular composition gradient.

Using single-isomer octa(6-O-sulfo)-γ-cyclodextrin for fast capillary zone electrophoretic enantioseparation of pindolol: Determination of complexation constants, software-assisted optimization, and method validation.

The present study describes a rapid and effective capillary electrophoresis (CE) method for the enantioseparation of pindolol using single-isomer octa(6-O-sulfo)-γ-cyclodextrin. The complexation parameters were determined under neutral and high pH conditions to identify optimal separation conditions using a theoretical model. Baseline separation of pindolol enantiomers was achieved within 6 min in a sodium/MOPS buffer, pH 7.2, with a selector concentration of 6 mM. The method was validated according to the ICH guidelines using imidazole as an internal standard. Low limits of detection and quantification were found, specifically 1.2 µg/mL and 4 µg/mL (0.6 µg/mL and 2 µg/mL per enantiomer), respectively. The calibration curves showed good linearity, with a coefficient of determination R2 ≥ 0.999 over a 5 - 55 µg/mL concentration range and over a 50 - 300 µg/mL concentration range of the racemic mixture. The relative standard deviations (%RSD) of intra-day and inter-day precision were lower than 8% at LOQ level, lower than 3% at 50 µg/mL level and lower than 1.5% at 300 µg/mL level. Accuracy ranged from 95 to 103% (106% at LOQ level). The proposed method was successfully tested on a medical formulation of Visken® Sandoz intravenous solution and Visken® Teofarma pills for oral use.