STUDIA CHEMIA - Issue no. 2 / 2021 - Table of contents

In Memoriam: In Memoriam Prof. Emil Cordoș Ph.D. 1936-2021

Keywords:

The aim of this study was to provide a regional pattern and characteristics of essential elements in several medicinal plants from North Macedonia and Romania. The content of Ca, Mg, Al, Fe, Cu, Ba and Zn was determined by ICP-OES while Na and K by FAES in some medicinal plants belonging to sixteen families. Similar profiles of elements with a high content of Ca, Mg and K were observed. Peppermint and blackberry from both countries showed extreme content in Al and Fe. A symmetric distribution for K, Ca and Zn and an asymmetric one for Na, Al, Fe and Ba were found in medicinal plants from both countries. Potassium, Ca, Mg, Al and Fe could be considered as markers for growing area. Principal Component Analysis highlighted that the variability of elements content was described by four factors (83.4%) in North Macedonia and three factors (70.0%) in Romania. The first factor could explain the influence of soil nature upon variability of elemental composition, calcareous in North Macedonia (Mg and Ca – 29.4% variance) and a rich one in hydroxides in Romania (Al and Fe – 33.1% variance).

Keywords: essential element, medicinal plant, inductively coupled plasma optical emission spectrometry, flame atomic emission spectrometry, Principal Component Analysis, two-way joining Cluster Analysis

Different assortments of beers, packed in cans and bottles, exist on the market. Beer has a complex and balanced composition, phenolic compounds being one class of bioactive constituents that are of particular interest due to their essential role in the brewing process, physical stability and aroma of this beverage. The aim of this paper is to integrate antioxidant and pro-oxidant evaluation, total phenolic content (TPC) determination, chromatographic fingerprinting and chemometric methods in order to study the influence of the variety and the packing type for beer assortment recognition. The antioxidant capacity evaluation was done by 2,2-azinobis(3- ethylbenzothiazolyne-6-sulphonic acid) radical cation (ABTS) assay and Folin-Ciocalteu method was used and to determine the TPC. Thin-layer chromatography (TLC) and high performance liquid chromatography (HPLC) were applied to obtain the fingerprints of beers. The results show that antioxidant and pro-oxidant capacities, the TPC and the chromatographic fingerprints were influenced by the packing type, the assortment, the alcoholic content and the colour of beer. Principal component analysis and cluster analysis were applied to study the influence of the variety and bottling type of beers on their characteristics. The results demonstrate that by integrating various methods the classification of beers based on their assortment was enable.

Keywords: antioxidant capacity, pro-oxidant capacity, phenolics fingerprint, beer assortment, TLC, HPLC, PCA, cluster analysis

The objective of this study was to determine the fatty acids content from Rosa canina and Prunus spinosa plant fruit oil via ultrasoundassisted process. The extracted oil’s fatty acids were converted into fatty acid methyl esters (FAME) before gas chromatography analyses (GC) equipped with flame ionization detection (FID). Results showed that Rosa canina oils contain mainly polyunsaturated fatty acids with the linoleic acid as the major fatty acids (62.3%) followed by oleic acid (28.6%), whereas Prunus spinosa oils contain 46.2% oleic acid and 32.6% linoleic acid. Rosa canina oil could be used as potential source of linoleic acid.

Keywords: Rosa canina, Prunus spinosa, Fatty acids, GC-FID

Reaction of the free-radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) with dihydroxyfumaric acid (DHF) and ascorbic acid (AA) was investigated in ethanolic media and in wine simulated matrix by using a stopped-flow system. The antioxidant activity for both acids were significantly higher in wine matrix, the observed constants (kobs) being about 3 s-1 for DHF and 0.66 s-1 for AA. Synergic and anti-synergic interactions of DHF and AA against DPPH were also investigated. A strong anti-synergic effect was noticed in ethanol (kobs < 0.35 s-1). In wine simulated matrix the constants were higher than in ethanol (kobs ≈ 1 s-1), but still too small for a synergic effect. Some explanations concerning the mechanisms of antioxidant action are proposed.

Keywords: dihydroxyfumaric acid, ascorbic acid, DPPH, wine matrix, stopped-flow

The interaction of (E)-4-(2-(7-bromo-10-ethyl-10Hphenothiazin- 3-yl)vinyl)-1-methylpyridin-1-ium (PVP) dyes with calf-thymus DNA was examined by spectrophotometric UV-vis absorption/emission titration and competitive ethidium bromide displacement. The association constant values were situated in 106 M-1 range, typical to cationic dyes containing the monocyanine chromophore system. The variation of the counterion of the cationic PVP dye from iodide to tetrafluoroborate produced dissimilarities in the interaction pattern with DNA. The PVP iodide competitively displaced the ethidium bromide (EB) from the EB-DNA system, thus suggesting the intercalation ability of the dye, while the PVP tetrafluoroborate did not supported the intercalation of the dye.

Keywords: cyanine dyes, phenothiazine, DNA binding, association constant

Nanotechnology is an attractive and challenging science focused on the materials at nanoscale level and their employment in a wide variety of applications. Its applications in (nano)medicine are constrained due to the main concerns in understanding and predicting the behavior of nanoparticles (NPs) in complex biological fluids. The properties of NPs can be strongly influenced by the surrounding conditions, such as pH and composition, in terms of aggregation status, chemical reactivity and surface chemistry. In this regard, this review intents to provide some insight into the performance of complex biological fluids associated with nanomaterials. In particular, the behavior of AgNPs and AuNPs in simulated biological fluids that must be addressed to develop an appropriate system for medical applications, from a chemical perspective, mostly related to the physicochemical characteristics of NPs and simulated biological fluids and their possible interactions (mechanisms) was considered. Furthermore, the fate of AgNPs and AuNPs during the gastrointestinal transit from an in vivo experimental perspective, as well as their potential impact on gut microbiota was also systematized.

Keywords: silver, gold, nanoparticle, simulated biological fluid, gastrointestinal microbiota

The paper presents the validation of a method for the determination of exchangeable cations (K+, Na+, Ca2+ and Mg2+) in zeolites by inductively coupled plasma optical emission spectrometry (ICP-OES), after extraction in ammonium chloride solution. Amongst the analytical techniques that can be used for exchangeable cations measurement, ICP-OES provides rapid, robust, multi-element analysis on a wide range of concentrations. The exchange capacity is one of the most important parameters of zeolites since it indicates their adsorption capacity in different processes. Method validation is an essential requirement for testing laboratories in order to provide trustworthy results in accordance with ISO/IEC 17025:2017 standard. The main figures of merit were studied, and the measurement uncertainty was assessed. The selectivity assay showed no significant non-spectral matrix effect. The linearity study was conducted for the calibration curves in the range of 0.02–20 mg L−1 for each exchangeable cation. Limits of quantification were 0.005 mEq 100 g-1 for Na+, 0.011 mEq 100 g-1 for Mg2+, 0.002 mEq 100 g-1 for K+, 0.003 mEq 100 g-1 for Ca2+. Relative standard deviations of repeatability (RSDr) (n=6 parallel samples) were 4.50 % for Na+, 4.43 % for Mg2+, 6.55 % for K+ and 5.53 % for Ca2+. Recoveries (%) estimated using a certified reference material (CRM BCS-CRM 375/1), for total content of cation oxides were in the range 92–103 %. Fourteen zeolite samples from Racos deposit, Romania were analysed, and according to the chemical composition and Xray diffraction the main mineral in zeolitic tuffs is clinoptilolite-type. The obtained figures of merit demonstrate that the method has a suitable level of precision and accuracy for the intended purpose.

Keywords: zeolites, exchangeable cations, ICP-OES, method validation, cation exchange capacity

This study was carried out with the aim of increasing and determining the activated zeolites’ adsorption capacity by testing their efficiency on petroleum hydrocarbons. Natural zeolite samples were sequentially studied after thermal and chemical activations. The results indicated that after the activations, the zeolite samples gained an increasing adsorption capacity of petroleum hydrocarbons. Furthermore, the zeolites with small particulate sizes (< 10 μm) have a higher adsorption capacity than the zeolites with a granulometry of 1-3 mm. The metal content ranged between 4200-7400 mg/kg Na, 15090-22990 mg/kg Ca, 2670-3950 mg/kg Mg, 19470- 19670 mg/kg K, 6140-7210 mg/kg Fe and 149-178 mg/kg Mn. Mineralogical analyzes (X-ray diffraction - XRD and scanning electron microscopy - SEM) were applied for the characterization of the zeolites. According to the XRD results, the zeolites are characterized by a 64 % crystallization level. The main mineral which was determined was Clinoptilolite-Ca. The SEM micrographs indicate the morphology of zeolite surfaces.

Keywords: zeolites, thermal treatment, chemical activation, adsorption capacity

Ba and Sr may occur in relatively high content in natural zeolites and can contribute to the zeolites ion-exchange properties. In addition, some soluble compounds of Ba and Sr can be toxic, thus their determination is important. The aim of this paper was the development and validation of a method for determination of Ba and Sr in zeolites based on microwave-assisted acid digestion and inductively coupled plasma optical emission spectrometry (ICP-OES). For validation, a certified reference material (BCS-CRM 375/1) was used in the accuracy study, and the obtained recoveries were 92 ± 10 % for Ba and 95 ± 12 % for Sr. A mixture of HNO3:HCl:HF of 3:9:2 (v/v/v) and a digestion time of 40 min were found to give recoveries in the range of 80-120 %. The obtained LOQs in ICP-OES allowed the quantification of concentrations above 5.0 mg kg-1 Ba and 3.8 mg kg-1 Sr. The method was applied for the determination of Ba and Sr in five zeolite samples, and concentrations of 422 – 580 mg kg-1 for Ba and 115 – 183 mg kg-1 for Sr were found. The obtained performance parameters were in agreement with the requirements of international guidelines regarding methods validation.

Keywords: trace metal, aluminosilicate, barium, strontium, ICP-OES, microwave digestion

An ex-situ method for determining the major elements in the high silicate matrix using portable XRF spectrometry (pXRF) was developed. The calibration is based on the dilution of a matrix-matched certified reference material BCS-CRM No. 376/1 Potash Feldspar with analytical grade SiO2. Significant correlation coefficients for linear regressions were obtained for all major oxides. This approach of instrument calibration has as the principal advantage the use of a single certified reference material, which reduce the cost of analysis. The limits of detection were evaluated from measurement of SiO2 considered as blank. The method accuracy of the developed calibration was checked in the recovery study of two certified reference materials (BCS-CRM No. 309 Sillimanite and BCS-CRM No. 375/1 Soda Feldspar), with geological matrix, and the recoveries rate were in the range of 85 – 110 %. The relative expanded uncertainties (k = 2, P = 95%) calculated from CRM analysis were of 6.99% for Al2O3, 3.56% for Fe2O3, 4.82% for CaO and 4.31% for K2O. The proposed methodology is a green analytical method, allowing fast and accurate analysis of geological samples without use of chemical reagents.

Keywords: X-ray fluorescence, major element, zeolite, instrument calibration, matrix-matching calibration, ex-situ procedure

One of the most important factors that influence the quality and resistance to chemical and microorganism degradation of paper, historical artifacts and art works is pH. Despite the simplicity of electrochemical devices that are mostly used nowadays for pH determination, some of them have limitations in terms of precision and time response. In this study, a rapid, simple, and highly precise method for determination of pH of paper was developed using non-destructive reflectance spectroscopy and commercial non-bleeding pH indicator test strips. The calibration curve was constructed using standard Britton-Robinson buffers and was done in the 4.00 – 9.50 pH range. Using univariate regression analysis, the largest linearity domain (R2 = 0.9992, p < 0.000) was found to be at 590 nm wavelength, as established from the loadings plot for a PCA analysis. The proposed method, alongside other two known methods, were applied on three real samples, including a 1710 Greek New Testament. No statistical significance (p > 0.05, ANOVA) was observed between the three methods, supporting the accuracy of the proposed method. Fischer test reveals a strongly significant higher precision for the tested method (p < 0.01). The values of the determined pH for the three real samples were 8.47±0.03, 7.78±0.07 and 7.99±0.08.

Keywords: non-destructive method, pH determination, reflectance spectroscopy

This paper presents our results concerning the feasibility of selective potentiostatic electroextraction of copper, tin and lead from leaching solutions obtained during the recycling of base metals from waste printed circuit boards. Applying this protocol, in a first stage, the concentration of Cu ions from the leaching solutions can be lowered, with acceptable efficiency, below 0.5 g/L. To avoid the contamination of Sn-Pb alloys with Cu, an intermediary step of Cu cementation on metallic Sn were proposed and tested. Finally, the potentiostatic selective electrodeposition protocol was successfully applied for the electroextraction Sn-Pb alloys. The experiments were performed in real leaching samples, using a Fisher type electrode as cathode. The obtained experimental results demonstrate that, controlling rigorously the imposed potential and corelating them with the solution composition, high purity Cu and Sn-Pb alloys deposits can be obtained, maximum contents of 99.96%, 99.83% and 82.62% being evaluated for Cu, Sn and Pb, respectively.

Keywords: waste printed circuit boards, potentiostatic selective electroextraction, copper recovery, tin and lead alloy electrodeposition

Taguchi experimental design was used to optimize the experimental parameters for Au sorption from ammoniacal thiosulfate solutions containing 2 mg/L Cu complexed as cuprous thiosulfate [Cu(S2O3)3]5− onto anion exchange fiber (METALICAPT® MFH11). An L9 orthogonal array was chosen to study the effect of three parameters, namely Au initial concentration (10-30 mg/L), fiber quantity (0.05-0.55 g) and temperature (20-30°C). The sorption tests were carried out in batch mode at a stirring rate of 500 rpm and pH of 9.3. The experimental data were processed using signal-to-noise ratio and the analysis of variance was used to determine the most significant parameters. The optimal conditions for Au sorption were found to be 30 mg/L Au concentration, 0.05 g of fiber and temperature of 20°C. The obtained results indicated fiber quantity as the most influential parameter on Au sorption with a contribution of 66%, followed by Au initial concentration with a contribution of 33%. In the optimal conditions, the sorption capacity of the fiber was found to be 16.8 mg/g, in good agreement with the predicted result by Taguchi method (16.7 mg/g). Further investigations are necessary to examine the elution behavior of gold from the fiber.

Keywords: gold sorption, anion exchange fiber, Taguchi experimental design, ANOVA

Recycling is one of most important steps toward circular economy. Since the quantity of waste of electrical and electronic equipment (WEEE) is increasing rapidly, it became crucial to know its composition to find adequate recycling solutions. Following this trend, the present study aims to find the major components of plastic components from 1997-2003 computer main boards. A new GC-MS method was developed and used to quantify the main volatile organic compounds of polystyrene PS (benzene, ethylbenzene), acrylonitrile butadiene styrene ABS (acetophenone, styrene, butyldiglycol) and polypropylene PP (n-Tetradecane, n-Hexadecane and n-Heptadecane). The extraction method was carried out using a saline water solution (10 % saline content; w:v) to extract the volatile compounds on SPME fibers under continuous agitation at 55 °C. The analytical method used a complex temperature program and a HP-5ms fused-silica capillary column of 30 m length × 0.25 mm I.D. × 0.25 μm film thickness (Restek, USA) to achieve separation of the compounds. The investigation of the major components of plastic components from 1997-2003 computer main boards using the developed method showed a decrease of ABS and PP major components from 1997 to 2003 and an increase of the major components from PS.

Keywords: WEEE, polystyrene, acrylonitrile butadiene styrene, polypropylene, GC-MS

The aim of this study was to evaluate the adsorption of rhodamine B (RB) from synthetic water using natural zeolites from Romania. The adsorption capacity of zeolite for RB removal was improved by heat treatment at 200, 400 and 600 °C. The chemical and structural characterization of untreated and thermally treated zeolites was performed using advanced techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis. The adsorption behavior of RB on activated zeolites was studied using Langmuir, Freundlich and Dubinin- Radushkevich isotherms. The thermally treated zeolite at 200°C gave the highest adsorption efficiency (97.9%) for RB adsorption from aqueous solutions. According to the obtained results, it can be concluded that thermally treated zeolite can be used as an effective adsorbent for the removal of RB from wastewater.

Keywords: zeolites, rhodamine B, thermal activation

To assess the spatial and temporal contamination with toxic elements (As, Cd, Cr, Cu, Pb, Ni, Zn), surface water and sediments were collected in 2019 and 2020, from Valea Sesii, a contaminated water stream in Romania. The toxic metal contamination of water was assessed using heavy metals evaluation index (HEI), heavy metals pollution index (HPI) and of sediments using contamination factor (Cf) and geo-accumulation index (Igeo). The metal concentrations were comparable within the two years, suggesting that the natural attenuation process was inadequate, and treatment technologies are required to improve surface water and sediment quality. The surface water presented high degree of metal contamination in 2019 as indicated by HPI > 100 and HEI < 10. The toxic metal concentrations in sediments were very high for Cd, Ni, Pb and Cu, with highest Igeo value for Cd and Cf for Ni. Surface water and sediments showed signs of high level of contamination in the sampling points located downstream of the copper mine discharge point, an improvement of their quality being noticed with distancing from the mining discharge area. This study is a first step for a comprehensive risk assessment and for an integrated environmental management.

Keywords: metal contamination, river water, sediments, HEI, HPI, contamination index, Igeo

This study was conducted with the aim of determining the quality and potential contamination level of water wells. Samples were collected from private water wells used as drinking water sources in Remeți locality, Maramures County, Romania. Remeți is situated near the protected area of the Upper Tisa River. Several physico-chemical indicators were determined, such as pH, electrical conductivity, dissolved oxygen, oxygen saturation, turbidity, temperature, ammonium, nitrate, nitrite, chloride, phosphate, iron, copper, sulphates, carbonate, bicarbonate and total hardness, due to their importance to human health and to the quality of the aquatic systems situated nearby a protected area. The quality status was assessed by using the water quality index (WQI), based on eleven parameters: pH, electrical conductivity, ammonium, total hardness, turbidity, nitrite, nitrate, chloride, sulphate, iron and cooper. The results indicated high amounts of ammonium and nitrate, while the WQI classified the studied water well samples into excellent and good quality categories. The WQI scores ranged between 27.7 and 65.1. The novelty of the study consists in the determination of the chemical composition of water wells from Remeti locality and in identification of some pollution processes which could affect human health if the studied waters are used as drinking water sources.

Keywords: water quality, physico-chemical parameters, water quality index

In the present study, the use of chicken manure leachate (CML) as a nutrient source for the cultivation of Chlorella spp. at laboratory scale was investigated. The concentration of total organic carbon (TOC) and biochemical oxygen demand (BOD) was monitored during 15 days of cultivation in CML. The changes of pH, conductivity, Cl-, PO43-, SO42-, NO2- and NO3- concentrations were measured during the growth period. The BOD and TOC reduction was 96.4% and 86.1%, respectively after 15 days of cultivation in CML. The Chlorella spp. biomass cultured in CML had a high protein content compared to the biomass grown in the BG-11 medium. The obtained results suggest the potential use of CML as a nutrient source for the growth of Chlorella spp.

Keywords: biomass, chicken manure, microalgae

The harmful effects of airborne dust have been long known, with numerous studies proving the danger it poses to human health. The paper presents a submicron size airborne dust particle monitoring system, built in collaboration by a laboratory equipment manufacturer and a national research and development institute. The system is designed for the automotive industry, the printed circuit board production lines, and the environmental monitoring. It can measure and record data continuously and the loss of the supply voltage does not lead to the loss of the monitoring history. The key element is the particle sensor itself, consisting of a laser diode assembly - CCD area, a suction pump with continuous operation, with constant electronically controlled flow and an electro-optical detector. The system is designed with the following specifications: the applicable particle size: 0.3 μm; 0.5 μm; 1.0 μm; sampling time: 1…599 sec; programmable (25 sec. by default); average count setting: 2; 4; 8; 16; 32; 64; ambient temperature range: operating at 40ºC; power: 220V / 50 Hz; power consumption: max. 25 VA; ABS housing, IP rating 54; dimensions (L x W x D): 260 x220 x 156 mm; weight: approximately 2.5 kg.

Keywords: suspended particulate matter, submicron particle monitoring, air quality, analytical instrumentation

CO2 emissions represent an actual problem for the environment. Additionally, the new demands for all chemical and physical processes request to be more eco-friendly. In this work, deep eutectic solvents (DESs), a relatively new class of solvents, were used for CO2 capture and desorption. DESs are more environmentally friendly than classical solvents. Two choline chloride-based DES – ethaline (ChCl:EG, 1:2 molar ratio) and reline (ChCl:U, 1:2 molar ratio) were prepared and characterized before studying their CO2 absorption – desorption capacity. The formation of eutectics was confirmed by FT-IR analysis and DESs were characterized in terms of pH, density, viscosity, refractive index, and electrical conductivity. The tests showed that ethaline had better CO2 absorption and desorption capacity than reline, which could be explained by several parameters.

Keywords: CO2 capture, deep eutectic solvents, green solvents

The mixing/agitation of time independent non-Newtonian fluids can be a challenge in many technological processes. In the present study, the influence of rheological parameters, K and n, on Reynolds number, power number and power consumption, for different concentration of carboxymethyl cellulose (CMC) solutions, 1%, 2%, 3%, 4 % and 5%, with shear-thinning behaviour, was analysed. The power consumption obtained by theoretical model and by an appropriate curve Po = f(Re) from experimental data, found in literature, was compared. The results have shown good agreement between calculated power number and the graphically determined values, and also minimal power consumption values comparable with those founded for the agitation of non-Newtonian liquids.

Keywords: mixing, agitation, Reynolds number, power number, power consumption, non-Newtonian fluids, shear-thinning fluids

The intensity of disasters is on an upward trend and inhabited areas are expanding into various risk areas, threatened by natural, technological or complex multi-hazards. The present study focuses on the analysis of Seveso-type economic operators whose activity is regulated by Law 59/2016 on the control of major-accident hazards involving dangerous substances. In Romania, the natural hazards that can trigger technological accidents in these sites are largely represented by earthquakes and floods. The analysis presented in this study was performed for a recurrence period of 475 years for earthquakes and 500 years for floods. The results of the analysis highlighted the sites in Romania that present specific Natech risks. Also, the possible technological accidents that may occur as a result of the manifestation of natural hazards have been identified for each site while a more detailed analysis was performed for the selected processes based on qualitative criteria. Finally, a ranking of these sites for Natech risks is presented considering the two natural hazards.

Keywords: Natech, Seveso, earthquake, flood

Food dyes are widely used in food products to offset the colour loss. To prevent fraud in the food industry, to ensure food safety and consumer health protection, it is necessary to implement fast, accurate and reliable methods for the analysis of dyes. A relatively fast method based on high-performance thin-layer chromatography (HPTLC) - photodensitometry was developed and applied to determine two synthetic food dyes (Sunset Yellow – E 110 and Ponceau 4R – E 124) in fish roe. TLC separation was carried out on silica gel plates, using the mixture isopropyl alcohol-ammonia (2:1, V/V) as mobile phase. Good separation of the dyes was achieved, the Rf values being 0.39 for E110 and 0.12 for E124, respectively. Due to the complexity of the matrix, sample preparation was performed into two steps: (i) extraction by ultrasound-assisted extraction with methanol-ammonia (1:1, V/V) and (ii) purification of the extract by ion-pair solid phase extraction (IP-SPE) on ChromaBond RP-18E cartridges. For both dyes, the overall recovery for the sample preparation step was higher than 91%, the relative standard deviation being less than 3.5%. The procedure was applied for E110 and E124 determination from a “red caviar” sample with the declared content of dyes.

Keywords: Food synthetic dyes, roe fish, ultrasound-assisted extraction (UAE), ion-pair solid phase extraction (IP-SPE), HPTLC

In this paper we report a biocatalytic approach for the efficient synthesis of anisyl propionate by direct esterification of anisyl alcohol with propionic acid mediated by commercially available Novozym 435, in presence of molecular sieves which serves for the efficient removal of water formed in the reaction. Process optimization was performed regarding the optimal solvent (2-methyltetrahydrofuran), temperature (60 °C), and molecular sieves load (100 mg/mL). Further scaling-ups were performed under optimal conditions increasing the substrates concentration up to 1000 mM with unaltered conversions in anisyl propionate (>95 % after 6 hours reaction time).

Keywords: lipase, aroma, flavor, biocatalysis, esterification, green solvent

The aim of this experimental work was the enhancement of water solubility of the lipid lowering drug, atorvastatin, by embedding it in polymer based micro-sized fibers, prepared by electrospinning. Characterization of the fibrous mats included morphological investigations, determination of drug content, disintegration time, small volume dissolution- and DSC studies. The electrospinning process was continuous without droplet formation. The obtained fibers were homogenous, continuous filaments with smooth surfaces. Average fiber diameters were slightly above 1 μm, while disintegration of fiber mats upon contact with water was almost instantaneous (three to ten seconds). Dissolution of the lipid lowering drug was almost complete, when using a solution feed rate of 1 mL/h.

Keywords: atorvastatin, electrospinning, PVP, microfibrous mats

Cannabidiol (CBD) is one of the most studied alkaloids found in Cannabis species. Also, its occurrence in Cannabis plants is higher in most of cases compared with the addictive compound named tetrahydrocannabinol (THC). This study aimed to evaluate CBD concentrations and stability in different commercial products and reconstituted oil. An UHPLC method previously published was applied. Three CBD oils and two powders marketed online together with a reconstituted oil were analyzed. The oils presented concentrations lower than stated on the label. The content of reconstituted CBD oils prepared similarly to the commercial oils decrease linearly with small differences based on the storage conditions. Thus, the CBD oil kept at temperatures of 5±0.3°C tends to decompose slightly slower compared with the oil kept at room temperature. A stabilizer may be needed to slow the decomposition process. Future studies for reconstituted formulation may be needed to establish if the type of oil used is influencing the decomposition process.

Keywords: CBD-oil, dietary supplements, storage, CBD powders, decomposition

This paper describes the preparation of plant extracts using solid-liquid ultrasonic extraction (sonoextraction), the characterization of prepared extracts and their bioinsecticidal activity. The studied raw vegetal material:Primula veris, Achillea millefolium, Origanum vulgare and Artemisia absinthium, was collected from the spontaneous flora of Romania, Moldova region. To assess the efficiency of solid-liquid sonoextraction process, the influence of some operating parameters such as solid/liquid ratio, extraction time, extraction temperature, and extraction efficiency was studied. The qualitative study has in view the interpretation of UV-VIS spectra recorded for the extracts, and the quantitative study consists in the estimation of total polyphenols and flavonoids content of prepared vegetal extracts. The resulted data indicate that the content of polyphenols and flavonoids is dependent of the extraction temperature, extraction time and solid/liquid extraction ratio. The bioinsecticidal activity of Origanum vulgare and Artemisia absinthium extracts was evaluated on the Acanthoscelides obtectus (commonly named as ladybug bean) using two application techniques (i.e. direct and indirect application using a cellulose disk as a porous material impregnated with extract that allows controlled evaporation), being registered a mortality rate of adults in the range of 35-55%. Therefore, the studied extracts proved to be effective in controlling ladybug bean from seed stores.

Keywords: Acanthoscelides obtectus (ladybug bean), bioinsecticidal activity, chemical characterization, vegetal extract, sono- extraction

The anticancer drug vincristine, known to act by inhibiting tubulin function in human cells, is shown to affect autoxidation rates in hemoglobin – either alone or under conditions where nitrite acts as an initiator in a nitrosative stress cascade. This behavior mirrors those observed by us with four other antitubulin agents - irinotecan, docetaxel, paclitaxel and vinorelbine.

Keywords: vincristine, hemoglobin, autoxidation, nitrite, oxidative stress, nitrosative stress, UV-vis

Ms. Anca Becze is the corresponding author for the previously published article: Evaluation of The Antioxidant Capacity and Total Polyphenols in Different Fruit Teas, STUDIA UBB CHEMIA, LXI, 3, Tom II, 2016 (p. 505-514). Ioan Simon, Dorina Simedru, Lucian Dordai, Emil Luca, Vanda Fuss, Anca Becze*, *Corresponding author email: anca.naghiu@icia.ro

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