In this study, metal complex of Copper(II) with a Schiff base derived from 2,2-dihydroxyindane-1,3-dione and 2-aminoethanoic acid were synthesized. The product are characterized by spectral methods. The antimicrobial activity was tested on reference bacterial strains and the antioxidant capacity was analyzed by using the DPPH and FRAP methods. The spectral data indicates that the Schiff base coordinates the Copper(II) as a tridentate ONO donor ligand. The compounds showed weaker antimicrobial activity on certain tested microorganisms. In vitro testing of antioxidant activity showed a significant reducing ability of the complex, as well as inhibitory activity against DPPH radicals.

: The chemistry of complex compounds containing imine ligands is attracting significant attention from research-ers today. In this work, complexes of selected transition metals (Cu, Co, Ni and Fe) with imines based on ninhydrin and amino acids methionine and cysteine were synthesized. FTIR and UV/VIS spectroscopy were used for structural characterization. Antioxidant activity of the complex was analyzed by the FRAP method. The synthesized compounds showed a significant reducing ability, ranging from 221.94 to 756.30 µmol/L. In vitro antimicrobial activity was tested on strains from the ATCC collection. Inhibitory activity against the tested microorganisms was recorded, and the zones of inhibition ranged from 10-24 mm. Preliminary research shows that these compounds have biological potency, but more detailed in vitro and in vivo studies are required for their use.

Cloud point extraction (CPE) is an attractive technique that reduces solvent con- sumption and exposure, disposal costs, and process time. This method has an im- portant practical application and is used to separate and concentrate the analyte as a step before its determination, and after the formation of a poorly water-soluble complex. Use of nonionic surfactants as ”green solvents” which represent an effec- tive alternative to toxic organic solvents (in classical extraction), along with other advantages, such as low cost and low flammability, makes this method attractive and worth further research and optimization. This paper presents a detailed de- scription of the principles, procedure, advantages, disadvantages and application of CPE.

Schiff bases are organic compounds formed by the reaction of the primary amine with carbonyl compounds (aldehydes or ketones). These are mainly bi- or tridentate ligands capable of forming very stable complexes with transitional metals. They are used as catalysts in oxygenation, hydrolysis, electro-reduction and decomposition reactions. Many Shiff bases show significant anti-tumor and antimicrobial activity, which is why they are the subject of research by many scientists in the world. In this paper Schiff's base from benzidine and 1,3-diphenyl-1,3-propanedione was synthesized. To characterize the product, FTIR spectroscopy and stereo-microscopy were used. In order to determine biological activity, antibacterial, antifungal and antioxidant activity of the product was tested. The results showed that the interaction of benzidine and 1,3-diphenylpropandione results in a Schiff base showing antibacterial, antifungal and antioxidant activity. Keywords: Schiff base, benzidine, FTIR, UV/Vis, antimicrobial activity.

Green Tea, made from Camellia sinensis plant leaves, is one of the most popular drinks in the world. For the past decades, scientists have studied this plant in terms of potential health benefits. Research has shown that green tea helps prevent stroke, malignancy and infections. In this paper, antioxidant activity and total phenol content of 4 samples of green tea from local Tuzla stores were investigated, of which two were of foreign origin. The antioxidant activity of the samples was analyzed using FRAP and DPPH methods. The obtained results show that the highest content of total phenols and the largest antioxidant capacity has a sample of foreign origin. The content of total phenols in the samples ranges from 60.01 to 79.34 mg GAE/g. The highest FRAP value is 3.34 mmol/g. The antioxidant capacity was also confirmed by the DPPH method. The IC50 value ranges from 0.014 to 0.030 mg/mL. Keywords-Phenol, FRAP, DPPH, Green Tea

A Cloud point extraction (CPE) procedure was presented for preconcentration of lead(II) ions, after complexation by 18-crown-6 (18C6) and extraction with Triton X-100 at proposed experimental conditions. After separation of surfactant - rich phase, content of Pb(II) ions in remaining solution was measured by Flame Atomic Absorption Spectrometry (FAAS). The experimental conditions such as pH, temperature, concentration of Triton X-100, concentration of 18C6, incubation time, type and concentration of added electrolyte, were evaluated. Results showed that among investigated electrolytes (NaCl, Na2SO4 and Na2CO3) the amount of 0.9 mol/L Na2CO3 lowers cloud point temperature of Triton X-100 to 22?C (room temperature during the experiment), thus simplifying the extraction procedure. After an incubation time of 5 minutes and using the concentration of 1.2?10-3 mol/L Triton X-100 and 1.5?10-4 mol/L 18C6 (1:1 stoichiometric ratio for 18C6:Pb), 60% of lead (II) ions were efficiently removed from investigated solution.