Facultatea de Chimie şi Tehnologie Chimică / Faculty of Chemistry and Chemical Technology
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Item Dynamics of the self-purification processes in the waters of the Dniester river during the years 2015-2024 (Dubasari - Vadul lui Voda section) [Articol](2025) Cisteacov, Maxim; Duca, Gheorghe; Blonschi, Vladislav; Gladchi, Viorica; Lis, Angela; Bunduchi, ElenaIt has been evaluated the dynamics of the self-purification processes of the Dniester River waters in the section from Dubasari to Vadul lui Voda based on the analysis of the parameters: biochemical oxygen demand (BOD5), chemical oxygen demand (CODCr), thiol content, and the inhibition capacity of the waters in carrying out chemical self-purification processes through free radicals (ΣkiSi). According to the BOD5 values, the Dniester waters belong to quality classes II and I, and according to the CODCr parameter, they fall into quality classes II and III. The thiol content is typical of fresh waters (10⁻6 M), and they are of natural origin. The inhibition capacity classifies the river's waters as slightly and moderately polluted. Along the river, were observed a decrease in biological self-purification processes and an increase in the intensity of free radical processes in the Criuleni area, indicating an additional inflow of reducing compounds into the Dniester waters from its tributary, the Raut River. Additionally, a tendency was noted for the aquatic environment quality restoration in the Vadul lui Voda area.Item Influența condițiilor de procesare asupra conținutului de antioxidanți în fructus Rosae [Articol](CEP USM, 2024) Grigoraș, Carolina; Blonschi, Vladislav; Duca, Gheorghe; Nica, SimonaFructele de măceș sau Fructus Rosae este un produs vegetal medicinal bogat în vitamine (A, B, C, D și E), minerale (Ca, Fe, K, Mg, Mn, S, Si și Se), polifenoli și are capacitate antioxidantă înaltă. Cel mai mare dezavantaj însă al vitaminei C, extrasă din produsele vegetale, este că aceasta se descompune ușor sub influența oxigenului, a condițiilor de procesare și păstrare din cauza fermentului ascorbinaza. A fost determinat regimul optim de temperatură și forma fructelor de măceș pentru a menține un conținut înalt de vitamina C și alți antioxidanți, responsabili de activitatea biologică a produsului vegetal medicinal. S-a stabilit că regimul optim de temperatură necesar dezactivării ascorbinazei este de 60°C timp de 30 minute, de asemenea forma produsului integral sau pulbere nu afectează esențial activitatea antioxidantă demonstrată prin metoda ABTS a ambelor forme.Item Rolul cobalaminei în procesele de autopurificare radicalică în mediul acvatic [Articol](CEP USM, 2024) Lis, Angela; Gladchi, Viorica; Blonschi, Vladislav; Cisteacov, Maxim; Bunduchi, ElenaThe main purpose of this research is to study the role of Cyanocobalamin (CNCbl) in aquatic ecosystems. The spectrophotometric method was used to determine the inhibition capacity and the concentration of OH radicals using PNDMA traps. As a result, it was found that, on the one hand, CNCbl is a reducing substance and leads to the consumption of oxidative equivalents, resulting in its oxidation. High inhibition capacity values and low OH radical values confirmed this. On the other hand, under irradiation, CNCbl can also act as a sensitizer. It actively absorbs photons in the UV and visible range, transitions to an excited state, and then transfers the electronic excitation energy to dissolved oxygen in water, forming active species such as singlet oxygen and superoxide radical anion. In the presence of protons, the superoxide radical anion is reduced to hydrogen peroxide, which generates OH radicals upon irradiation. From the obtained results, it can be seen that under the conditions of natural aquatic systems, CNCbl will not disturb the processes of radical self-purification.Item Stabilirea impactului poluării cu vitamina B6 asupra capacității de autopurificare a sistemelor acvatice naturale (lacuri) [Articol](CEP USM, 2024) Bunduchi, Elena; Gladchi, Viorica; Cisteacov, Maxim; Lis, Angela; Blonschi, Vladislav; Duca, GheorgheIn the framework of this research, it was aimed to establish which concentrations of vitamin B6 can be considered triggers of the pollution phenomenon in natural aquatic systems of the lentic type, such as the Danceni and Ghidighici lakes. The modeling was done on microcosm type systems. The pollution and auopurification processes were monitored according to the quality indicators for natural waters: pH, permanganateometric oxidizability (CCOMn), degree of saturation with dissolved oxygen (OD, mgO2/L) and inhibition capacity (Σki[Si], s-1). Research shows that natural waters can become vulnerable to vitamin B6 pollution in concentrations of the order of ≤ 0.5·10-4 M, because self-purification processes fail to eliminate the pollution caused by these concentrations, only slightly attenuating it. The consumption of active forms of oxygen, OH radicals, important particles of the chemical self-purification process of natural waters, highlight even more the negative impact of the pollution of aquatic systems with vitamin B6.Item Valorificarea florei spontane autohtone cu potențial în producerea farmaceutică și cosmetică [Articol](CEP USM, 2024) Grigoraș, Carolina; Blonschi, VladislavIn order to capitalize on the medicinal plant product from the autochthonous spontaneous flora, the rosehip fruit of Rosa Canina l. was standardized. Thus, fruits were collected from 3 geographical areas of the Republic of Moldova, the plant product was later analyzed according to the parameters indicated in the pharmacopoeia. The fruits were subjected to macroscopic and microscopic analysis to confrm authenticity and the following parameters were considered in the quantitative analysis: moisture, total ash, ascorbic acid content. The results revealed that the geographical area and climatic conditions influence the development and ripening of the rosehip fruits, as well as the content of ascorbic acid.