The cyclic voltammogram recorded in the potential range between 0 V and 800 mV with scan rate of 100 mV s −1 was used to determine the measure of antioxidants content (antioxidant capacity) present in Sambucus nigra L. extract. The antioxidant capacity of the extract was 4.06 mg GAE g −1 fw (mg of gallic acid equivalents per gram of fresh weight of the extract). The corrosion inhibition efficiency of Sambucus nigra L. extract on aluminium, copper, and bronze in 3 % NaCl solution was studied by potentiodynamic polarization and electrochemical impedance spectroscopy. Polarization data showed that extract acted as a mixed-type inhibitor, that the corrosion inhibition process was spontaneous physical adsorption (Δ G ≈ –16 kJ mol –1 ) of the extract molecules on metals surfaces and followed Freundlich isotherm. Impedance spectroscopy studies revealed that increasing the concentration of extract reduced the double-layer capacitance and increased the charge transfer resistance. The highest inhibition efficiencies (Cu: ~ 57 %, CuSn14: ~74 % and Al: ~58 %) were achieved for an extract concentration of 1.0 g L –1 .

Plant extracts are increasingly being examined in the corrosion inhibition of metal and alloys in various environments due to their potent antioxidant properties. The use of Artemisia annua L. aqueous extract (AAE) as an aluminium alloy 5083 (ALA) corrosion inhibitor in artificial seawater (ASW) was investigated using electrochemical tests and spectroscopy tools, while the active biocompounds found in AAE were analyzed using high-performance liquid chromatography (HPLC). Electrochemical results showed that AAE acts as an anodic inhibitor through the physisorption (ΔG ≈ –16.33 kJ mol−1) of extract molecules on the ALA surface, thus reducing the active sites for the dissolution of the alloy in ASW. Fourier-transform infrared spectra confirmed that phenolic acids found in AAE formed the surface layer that protects ALA against the corrosive marine environment, while HPLC analysis confirmed that the main phytoconstituents of AAE were chlorogenic acid and caffeic acid. The inhibition action of phenolic acids and their derivatives found in the AAE was based on the physisorption of caffeic acid on the ALA surface, which improved physicochemical properties of the barrier film and/or conversion of Al3+ to elemental aluminium by phenolic acids as reducens, which slowed down the diffusion rate of Al3+ to or from the ALA surfaces. The protective effect of the surface layer formed in the presence of AAE against ASW was also confirmed by inductively coupled plasma–optical emission spectrometry (ICP-OES) whereby the measured concentration of Al ions after 1 h of immersion of ALA in the pure ASW was 15.30 μg L−1 cm−2, while after the addition of 1 g L−1 AAE, the concentration was 3.09 μg L−1 cm−2.

Milk is a product of the mammary gland obtained by proper and regular milking of healthy, properly fed cows, sheep, goats, without adding or taking anything away.This paper describes modern methods used for milk analysis and their working principle. 30 samples of raw milk were collectedas follows: 10 samples of cow, 10 samples of goat and 10 samples of sheep raw milk.The obtained results of raw milk quality parameters were processed, analyzed and compared with the maximum permissible concentrations prescribed by the Ordinance on raw milk.The work was written by the method of prospective study (experimental research). Milk testing was conducted during the period from 1 March 2020 to May 1, 2020.Samples were collected from primary producers of raw milk from the territory of Canton 10 in the manner prescribed by the Regulation on the method of sampling milk. They were transported and analysed in the Laboratory for Quality and Microbiology of Raw Milk - Department of Food and Veterinary Medicine of Canton 10.During this period, tests of raw milk were performed on the MilkoScan 7 device , a milk analyzer that works on the principle of close infrared spectroscopy with Fourier transform.

The corrosion behavior of copper, tin, and bronze CuSn14 is studied in simulated acid rain (pH 4.5) by electrochemical techniques, cyclic voltammetry and electrochemical impedance spectroscopy. The potentiodynamic formation of anodic oxide film on copper and tin is described in terms of high‐field model. Cyclic voltammetry shows that dissolution of bronze is higher than of pure copper metal in acid rain. Electrochemical impedance spectroscopy data reveal that oxide films formed on copper and tin have a higher resistance and suppressed diffusion process through the surface layer than the oxide film formed on bronze CuSn14 at the same conditions.

Extract of Alchemilla vulgaris L. was investigated as eco-friendly corrosion inhibitor for aluminium in 3 % NaCl using electrochemical techniques. According to the results, inhibition efficiency increases with the increase concentration of extract and the highest efficiency (~80 %) is recorded for the maximal concentration of extract (1.0 g L–1). The inhibition activity of extract occurs by the spontaneous physisorption (ΔG ≈ –16 kJ mol–1) on active sites of aluminium surface that follows Freundlich isotherm. Polarization curves showed that Alchemilla vulgaris L. extract act s a mixed-type inhibitor. The effect of temperature on the aluminium corrosion and inhibition action of extract was studied and the result showed that the corrosion rate increased and the inhibitor efficiency decreased with increase of temperature. The calculated values of the activation energy confirmed presence of inhibitive Alchemilla vulgaris L. extract on aluminium surface.

The inhibition of copper corrosion by Helichrysum italicum extract (HI) in simulated acid rain was investigated using electrochemical techniques. Results indicate an increase in corrosion inhibition efficiency with the HI extract concentration. The inhibitive process was assumed to occur via adsorption of the extract on the metal surface. The thermodynamic data indicated physical adsorption and followed the Freundlich isotherm. The effect of temperature on the copper corrosion was studied. The value of the activation energy confirmed physisorption of extract molecules on the copper surface. The concentration of Cu ions released into solution, measured by atomic absorption spectrometry, was in accordance with the electrochemical results.

The adsorption and corrosion inhibition of alkanethiols self-assembled monolayer on the copper surface in simulated acid rain were investigated by electrochemical techniques. Self-assembled monolayer (SAM) was formed by 1-octanethiol (OT), 1-dodecanethiol (DT) and 1-octadecanethiol (ODT) molecules on copper surface. The experimental results showed that inhibiton efficiency increases simultaneously with increase of concentration and chain length of thiols. At the concentration of 0.5 mmol L ─1 , 1-octadecanethiol (ODT) acts as effective corrosion inhibitor with inhibition efficiency of ~ 90%. The adsorption of alkanethiol self-assembled monolayer on the copper surface was investigated by polarization measurements. The adsorption of SAMs on the copper surface followed Langmuir isotherm and the standard Gibbs energy indicated that the adsorption mechanism of OT, DT and ODT on copper is the hybrid type of physical and chemical adsorption. Values of Gibbs energy ranging from ─24 kJ mol ─1 for OT to ─32 kJ mol ─1 for ODT indicate that the chemisorption part in the adsorption mechanism prevails with the increase of alkanethiols chain length.

Abstract The effect of Satureja montana L. extract (SM) and phenolic fraction of Satureja montana L. (PF) on the corrosion behaviour of iron in 0.1 mol L-1 sodium chloride solution was studied by electrochemical techniques, UV/Vis spectrophotometry and atomic absorption spectrometry. The results of all techniques showed that SM and PF contributed to iron corrosion inhibition. The calculated inhibition efficiency values were about 45% for SM and 55% for PF. Results indicate that the inhibitive action occurs via a precipitation of the Fe-complex onto the iron surface which resulting in a decrease of the passive current density. The atomic absorption spectrometry (AAS) method was applied to the quantitative determination of iron in solution. The obtained results demonstrated good agreement with results obtained by electrochemical techniques.

The aqueous extract of the Helichrysum italicum leaves (HI) is tested as a corrosion inhibitor of an iron in a simulated acid rain using potentiodynamic polarisation, cyclic voltammetry and electrochemical impedance spectroscopy. Results of all electrochemical methods indicate an increase of a corrosion inhibition efficiency of the iron with the HI extract concentration. Maximum inhibition efficiency (~ 50 %) is obtained at 2.0 g L–1 HI extract. The inhibitive action is assumed to occur via an adsorption of the HI extract on the iron surface. Results indicate that the adsorption process is spontaneous and follows the Freundlich adsorption isotherm. According to the calculated ΔG value (~ 15 kJ mol–1), the corrosion inhibition of the iron occurs predominantly via a physisorption of the HI extract. The concentration of iron ions released into a solution, measured by atomic absorption spectrometry, is in accordance with the electrochemical results.

The effect of the aqueous extract of Achillea millefolium L . (AM) on the electrochemical behaviour of iron in a simulated acid rain solution (pH 4.5) was studied by electrochemical techniques cyclic voltammetry, potentiodynamic polarization and electrochemical impedance spectroscopy. Experiments were carried out over a wide range of AM concentrations. The results of all techniques showed that AM extract contributes to iron passivation. The films formed in the presence of AM extract were thinner and more resistive then the films formed in pure simulated acid rain solution. The AM extract adsorbed on the iron according to the Freundlich isotherm. The thermodynamic data indicated physical adsorption of the AM extracts on the iron surface. The concentration of the metallic ions released into solution, measured by atomic absorption spectroscopy, was in accordance with the results obtained from the electrochemical techniques.

The growth mechanism and properties of the oxide films on aluminium and 8090 Al-Li-Cu-Mg alloy were studied in simulated acid rain (pH 4.5) by electrochemical techniques, cyclic voltammetry and electrochemical impedance spectroscopy. The potentiodynamic formation of anodic oxide film on aluminium and 8090 Al-Li-Cu-Mg alloy surfaces were described in terms of high field model. This is justified by the obtained values of kinetic parameters: the electric field strength (~10 6 V cm –1 ), ionic conductivity through the film (~10 –12 S cm –1 and 10 –13 S cm –1 ) and half jump distance (~0.150 nm). The impedance data shows that protective passive oxide film on aluminium and Al-Li-Cu-Mg alloy can be formed spontaneously at the open circuit potential in the studied solution with a high resistance (119 k cm 2 for Al and 144 k cm 2 for Al-Li-Cu-Mg alloy). Both electrochemical techniques revealed that the oxide film on Al-Li-Cu-Mg alloy has better protective properties than pure aluminium. The concentration of the metallic ions released into solution from aluminium and Al-LiCu-Mg alloy and measured by atomic absorption spectroscopy was in accordance with the results obtained from the electrochemical techniques.