Hydrogels containing both carboxyl and hydroxyl functional groups have been prepared by γ-irradiation of either aqueous solutions of acrylic acid (AA) and mixtures of AA and 2-hydroxyethyl methacrylate (HEMA) in different ratios, or aqueous solutions of poly(AA), PAA, and poly(AA-co-HEMA) obtained via solution polymerization. A higher absorbed dose is required in order to prepare hydrogels from monomer solutions, compared with those from polymer solutions. The range for the absorbed doses was chosen so that the probability of crosslinking reactions is higher than that of degradation ones. As the radiation energy deposited in a sample increases, the equilibrium swelling degree and the average molar mass between crosslinks diminishes. Chemical transformations induced by radiation were investigated by means of FTIR spectroscopy and thermal analysis of polymers before and after irradiation. For all these systems, the formation of a three-dimensional network enhances the glass transition temperature and thermal stability, but a further increase in the crosslinking degree may have the reverse effect on the glass transition temperature. Depending on the preparation protocol and/or hydrogel composition, superabsorbent materials that can bind different compounds throughout side functional groups may be obtained.

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Capillary gas chromatography coupled with mass spectrometry technique was used for the assessment of low concentration of dinitrophenol pesticide, Dinocap in different spiked samples. For this purpose it has been spiked with Dinocap (15-200 µg/mL) five environmental matrices (a soil sample and two each samples of wine and grapes). The Dinocap degradation grade in these samples was also monitored. The extraction was performed in dichloromethane. The assessment of the Dinocap in the samples were also achieved by FTIR/ATR and reveals that after 18 days of pesticide application the recovery level of Dinocap decreased from 64% to 3% in grape, from 72% to 9% in soil, from 82% to 10% in wine at 18 days after pesticide application. The method described in this paper could be used for screening and identification of the named pesticide in other environmental samples with a spiking level as low as 2-20 µg/mL.

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