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The presence of phenolic compounds as one of the most common organic pollutants in natural water (surface and ground waters) has been detected as a worldwide problem. Very small concentrations of phenols affect the quality of both environmental and household waters, and directly or indirectly impact lives in aquatic systems and humans, as well. Most of the organic compounds, containing certain functional groups, such as amino, amines, carbonyl, hydroxyl, groups containing sulfur and others, have shown ability of adsorption on metal surfaces from aqueous solutions. Cyclic voltammetry (dE/dt = 100 mV s-1) with simultaneous monitoring of the double layer (dl) capacitance (at 100 Hz and 1 mV ac signal) was used for an adsorption study of phenol on polycrystalline gold from 0.5 mol dm-3 aqueous solutions of NaHCO3. Thus, in this study an effort was made to establish a fast method, an electrochemical procedure for qualitative and quantitative determination of phenols in natural water systems.

Dynamic electrical thermal analysis (DETA) is considered as a valuable technique for determination of polar polymer structure or changes in the polymer structure as a result of different treatments. Therefore, with this study, we wanted to check whether this technique can indicate structural changes in the PET packaging material in contact with specific media. Positive response give the opportunity to use the study of PET packaging dielectric properties after a programmed contact with some medium, to indicate possible interactions between packaging material and the medium, or packaging and foodstuff. It is also known that official simulants may have some drawbacks as migration of the potential contaminants depends on the interaction between the simulant and packaging and thus the values for measured migration could be exaggerated or too low.The possibility of DETA to indicate structural changes in the packaging material give also the opportunity to adjust the aggressiveness of some medium to the packaging, that is, some solvent, or mixture of solvents with different polarity, and thus to choose the most appropriate simulant – medium which will behave in the same way as the foodstuff.In this study we have chosen several conventional fatty food simulants: olive oil, isooctane, 3% acetic acid, and ethanol, and using the DET analysis we compared the influence of these media and the real foodstuff (mayonnaise) on the structure of poly(ethylene terephthalate) (PET) food containers.

The basic objectives of food packaging materials are to provide safety and to pre- vent physical damage of the product, to retain or improve sensory characteristics, to offer a pleasing appearance, to be functional, to facilitate distribution, to give dimensional stability, but also to be compatible with the requirements regulated by the law. Consumers’ demands for an extended shelf life of the product, as well as increased competition in the packaging industry, foster the need for continuous growth and application of innovative solutions for food packaging. While the tradi- tional packaging acts as a passive barrier toward atmospheric effects, the innovative packaging systems offer “active” interactions with the foodstuff, providing increased shelf life and improved quality of the product. The selection of the appropriate pack- aging material is influenced by many factors, and, among many packaging materi- als offered on the market, polymer materials and articles have a significant place. On the other hand, some interactions occur between the plastics and the food in contact. The migration of the low-molecular-weight components from the polymer packaging to the packed food is emphasized when the so-called active and intelli- gent systems are used. Therefore, all the issues related to the packaging materials for food and the substances used as part of the packaging systems, are elaborated in the directives and regulations of the materials and articles intended to come in contact with the food.