The composition of composites has a huge impact on the stability of tris-1,10--phenanthroline iron (II) complex during the determination of total iron. The subject of this work is the determination of the stability of tris-1,10-phenanthroline iron (II) complex in different composites. The composites with different concentration in which total iron was determined were alumina and zeolite. The stability of this complex was monitored in the time period of 0-60 min. The aim of this work is to determine the concentration of different composite samples and the time interval in which the stability of the complex is the highest. The spectrophotometric method was used for the determination. The tris-1,10-phenanthroline iron (II) complex with alumina is more stable at higher concentration of the samples. With zeolite, however, this complex is stable in a short time interval, regardless the concentration of the sample. This conclusion indicates the increase of absorption, which is a consequence of impede complex formation and creating a new complex. For this reason, this method has only a limited application.

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Family Lamiaceae (labia) includes a large number of cosmopolitan species including Thymus alpestris (Thyme) characterized by the presence of essential oils and phenolic compounds. It represents a perennial semi-shrubby plant. The antioxidant potential of thyme is due to the presence of polyphenolic acids and flavonoids. The topic of this paper is the extraction of thyme (Thymus alpestris) with 40% ethanol and 50% ethanol, using Soxhlet method (circulatory extraction), after which, the content of phenolics and flavonoids was determined in order to confirm the antioxidant potential of this plant species. The results show that 40% ethanol extract has the highest content of phenolics and flavonoids and the highest antioxidant potential, resultingly.

Interaction of hexavalent chromium and BSCF perovskite in water solutions ZASTITA MATERIJALA 56 (2015) broj 3 340