Electrochemical behavior of Telmisartan and optimum conditions for its assay were investigated by using cyclic voltammetry and square-wave voltammetry. All studies were based on the quasi-reversible and adsorption-controlled electrochemical reduction signal of TS at about À1.50 V versus Ag/AgCl at pH 10.0 in Britton-Robinson buffer. The peak current was found to change linearly with concentration from 1.69 nM (0.87 mg/L) to 27.5 nM (14.15 mg/ L). The limit of detection and the limit of quantification were found to be 1.05 nM (0.54 mg/L) and 3.49 nM (1.79 mg/L), respectively. The method was successfully applied to different samples with good recoveries at about 100 %.

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Multiple response optimizations of ultrasound-assisted water extraction (UAWE) conditions for the extraction of phenolic compounds from Morus nigra L. leaves were investigated. The experimental design and optimization of the UAWE were performed using response surface methodology (RSM) coupled with a central composite design (CCD). The optimum conditions of UAWE were determined as extraction time: 15 min, solvent:solid ratio: 85 mL/g and extraction temperature: 55 C. The optimized UAWE was compared with conventional extraction (CE) and it was observed that TPC (21.78 ± 0.50 mg GAE/g dw), TFC (11.70 ± 0.26 mg CAT/g dw), and TAA (66.37 ± 0.66% 1,1-diphenyl-2-picrylhydrazyl [DPPH]) in UAWE were higher than CE. The polyphenolic profile of the extracts obtained from both methods was evaluated and most of the 16 phenolic compounds especially chlorogenic acid (3.47 ± 0.06 mg/g dw), kaempferol (1.39 ± 0.02 mg/g dw) and quarcetin hydrate (1.92 ± 0.01 mg/g dw) were found in higher amounts in UAWE extracts. Practical applicationsBlack mulberry leaf extract, which is an important source for antioxidants and especially phenolic compounds, has a potential to become a supplement and functional food. Herbal infusion or tea prepared from black mulberry leaves can be an alternative to mostly consumed tea. The extraction and purification of natural antioxidant substances from plant sources make it possible to use these substances in the food industry. It is therefore important to optimize the extraction conditions of natural antioxidants and identify the substances in the extracts obtained. In this study, UAWE for high extraction yield at low temperature was also preferred to extract high quantities of phenolic compounds, which are heat sensitive. UAWE for phenolic extraction from black mulberry leaves was optimized by RSM. The optimized and improved extraction technique obtained from this study can contribute to the food industry by being used in large-scale industrial applications.

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Amidoximes are compounds bearing both hydroximino and amino functionality at the same carbon atom, and are thus closely associated with amides, amidines and hydroxamic acids. These compounds are of great importance for the synthesis of various heterocycles. The complex formation capability of amidoximes makes use of the determination of Cu, Hg, Pb, and group 8, 9 and 10 metals. Among the coordination compounds, those with Mo and W central atoms are the most important. Amidoximes have found numerous technological applications, such as corrosion inhibition, stabilizing polymers and paper strengthening. Amidoxime functionalized polymeric coatings are being developed for chemical electronic microsensors. Another important application of amidoximes is uranium recovery from seawater. Amidoximes, especially those carrying arylsulfonyl and pyridyl groups, were reported to have shown significant biological activities, like hypoglycaemic, analgesics, pesticides, herbicides, and antihypertensic. 1 To the best of our knowledge, there has been no report concerning the determination of the protonation constants of Nsubstituted amidoximes. Upon contiuning our studies on the determination of the protonation constants, 2,3 in this study we considered the protonation constants of some N-substituted amidoximes in 50% ethanol-water mixtures (v/v). Since these compounds sparingly dissolve in water, an ethanol-water mixture was used as a medium in titrations. The stoichiometric protonation constants were measured by a potentiometric titration method and calculations were carried out using PKAS computer software. 4 The structures and protonation constant values of the compounds under investigation are given in Table 1. ExperimentalAll of the compounds studied were synthesized as described previously 5,6 and checked chromatographically for purity. Stock solutions of these compunds were prepared in purified ethanol. 7 The standard amidoxime solutions were prepared in 50% aqueous ethanol. A 0.1 M perchloric acid solution was prepared in water and standardized by titration against primary standard sodium carbonate. Double-distilled deionized water was used throughout the experiments.Chemically pure sodium perchloride was used to maintain a constant ionic strength. Sodium chloride and sodium perchloride were purchased from Merck and used as received. An alkali solution containing 0.1 M NaClO4 was prepared using NaOH (Merck) in 50% ethanol-water mixture and standardized potentiometrically against a perchloric acid solution using Gran's plot techniques, allowing a determination of the dissolved carbonate impurity. 8,9 Potentiometric titrations were performed in a 80-mL glass vessel equipped with a combined pH electrode (Ingold), nitrogen inlet and outlet tubes, a magnetic stirrer and a titrant inlet. The electrode was modified by substituting its aqueous potassium chloride solution for a mixture of 0.01 M NaCl + 0.09 M NaClO4 saturated with AgCl. An Orion Model 720A pH ionmeter was used to measure the cell e.m.f. (the uncertainity of e.m.f. ...

In this article, the chemical compounds, antimicrobial and antioxidant activity of the volatile oil from leaves of Olea europaea L. cultivar from Turkey (Ayvalık) has been studied. The essential oil was provided with a Clevenger apparatus and analyzed by GC-MS/FID. This analysis leads to the detection of 42 compounds representing 99.59±1.15% of the total oil. The major constituents were a-pinene (9.82±0.33%), benzylalcohol (8.83±0.27%), phenethylalcohol (8.52±0.25%), 2-monopalmitin (8.13±0.28%), palmitic acid (5.53±0.41%), octadecanoic acid 2,3-dihydroxypropylester (5.84±0.42%), phytol (4.22±0.17%), and benzaldehyde (4.21±0.38%). The antimicrobial activities of the dried leaves essential oils were assessed against seven bacterial and four fungal strains. Significantly, the essential oil has an efficient antibacterial activity toward to the bacterial strains such as Bacillus cereus ATCC 14579, Candida albicans ATCC 10231, Enterococcus faecalis ATCC 29212 and Klebsiella pneumoniae ATCC 13883. The olive a leaf essential oils showed significant antimicrobial and antioxidant effects. This study gives more knowledge for the development of this crucial therapeutic plant.