The aim of this study is to evaluate the content of phenolics: the total phenols (TP), flavonoids (TF), anthocyanins (TA), as well as the total antioxidant capacity (TAC) in three sour cherry cultivars (Prunus cerasus L.) introduced to the southeast Serbia climate conditions. Among the researched sour cherries, ‘Oblacinska’ cultivar contained the highest amounts of all groups of phenolics, followed by ‘Cigancica’ > ‘Marela’. A significant difference were observed in the phenolic content among different cultivars and growing seasons (p<0.05), and the phenolic compounds were significantly higher in the growing season 2009. The examined cultivars possess a high antioxidant capacity, and all phenolics of highy correlation with TAC. The following compounds were identified and quantified using HPLC-DAD: 4 anthocyanins, the most abundant of which was cyaniding-3-glucoside in ‘Marela’ and ‘Oblacinska’, and cyanidin-3-glucosylrutinoside in ‘Cigancica’, and 4 hydroxycinnamic acids, the most abundant of which was neochlorogenic acid in all sour cherry cultivars. The growing and ripening process on the tree of sour cherry cv. Oblacinska was evaluated, also. The results showed significant increases in total phenols during the ripening, the total anthocyanins and total antioxidant capacity and 4 quantified anthocyanins, however the neochlorogenic acid decreased during the ripening. The study indicated that the growing and climate conditions in southeast Serbia are convenient for introducing sour cherry cultivars

Diclofenac, derived from benzeneacetic acid, is a nonsteroidal anti-inflammatory drug (NSAID) that is more usually found as a sodium or potassium salt with potent anti-inflammatory, analgesic, and antipyretic properties. Its mechanism of action is associated principally with the inhibition of prostaglandin synthesis (specifically, inhibition of cyclooxygenase).1) Diclofenac is indicated for a variety of conditions such as acute and chronic arthritis, rheumatoid arthritis, osteoarthritis, and ankylosing spondylitis. Diclofenac also has been demonstrated to be an effective migraine treatment in several placebo-controlled studies.2-4) It has been determined by a variety of analytical techniques, such as UV/Vis spectrophotometry, [5][6][7][8][9][10][11] fluorimetry, [12][13][14] reflectometry, 15) liquid chromatography, [16][17][18][19] and flow injection analysis with solid-phase spectroscopic detection. 20) However, as far we know, there is no kinetic-spectrophotometric method for the determination of diclofenac in the literature.The aim of this work is to develop a simple, rapid, reliable, precise and accurate kinetic method for the determination of diclofenac sodium in pharmaceutical preparations. The method is based on a ligand-exchange reaction. Diclofenac shows complexing ability with cobalt(II). The complex agreed with the empirical formula CoD 2 · H 2 O and the cobalt ions are co-ordinated through the carboxylate group of the ligand (diclofenac, D). 21,22) ExperimentalApparatus The reaction rate was monitored spectrophotometrically by measuring the rate of change of absorbance at 376 nm. The readings were performed on a Perkin-Elmer Lambda 15 UV/Vis spectrophotometer, connected to a thermo-circulating bath.pH measurements were carried out using a Hanna Instruments pH meter. In addition, high precision volume micropipettes (Lab Mate ϩ ) of 50, 500 and 1000 ml were used for handling or pipetting the solutions.The solutions were thermostated at 22Ϯ0.1°C before the beginning of the reaction.Potentiometric titrations were conducted using a Titrino 716 DMS in dynamic equivalence-point titration (DET) mode. The evaluation of EPs was based on the zero crossing of the second derivate of the titration curve.Reagents A diclofenac stock solution (1ϫ10 Ϫ3 mol l Ϫ1 as the sodium salt) was prepared from pharmaceutical 99.9% certified products supplied by a pharmaceutical laboratory (Galenika, a.d., Belgrade, Serbia). The solution was stored at 4°C. Working solution was prepared daily from this solution, as required, by dilution with water.Acetic acid solution (HAc, 10 mol l Ϫ1) was prepared from glacial HAc (Merck).1-Nitroso-2-naphthol solution (1ϫ10 Ϫ3 mol l Ϫ1 ) (Merck) was prepared by dissolving a known amount in 5 ml absolute ethanol and diluting it with water (total volume 50 ml).The stock cobalt(II) solution (1.7ϫ10 Ϫ3 mol l Ϫ1 ) was prepared by dissolving CoCl 2 ϫ6H 2 O (Merck) in water.Ionic strength was kept constant at 0.1 by adding an appropriate amount of NaCl solution (mol l Ϫ1). Analytical grade chemicals an...

A new inhibitory reaction is proposed and a kinteic method developed for the determination of ultra‐micro amounts of Mo(VI) on the basis of its inhibitory activity in oxidation of trimethylenediamine ‐N,N,N′,N′‐tetraacetic acid (TDTA) by KMnO4 in the presence of hydrochloric acid. Under optimal conditions the sensitivity of the method is 0.5 ng/cm3. The probable relative error is 2.9–3.5% for the concentration range 7.5–2.0 ng/cm3 of Mo(VI). The effect of certain foreign ions upon the reaction rate were determined for the assessment of the selectivity of the method. The selectivity of the method is relatively good. Kinetic equations were proposed for the investigated process. A method has been applied for determination of Mo(VI) in a certain kind of steel.

A new sensitive and simple kinetic method is developed for determination of traces of ascorbic acid based on its activated effect on oxidation of trisodium-2-hydroxy-1-(4-sulphonato-1-naphthylazo)naphthalene-6,8-disulphonato (red artificial color Ponceau 4R) by hydrogen peroxide, in the presence of Cu(II) as catalyst, in borate buffer. The reaction is followed spectrophotometrically by tracing the oxidation product at 478.4 nm within 1 min after addition of H 2 O 2 . The optimum reaction conditions are: borate buffer (pH = 11.00), Ponceau 4R (9.6·10 -6 mol/L), H 2 O 2 (2·10 -2 mol/L), Cu(II) (8·10 -7 mol/L) at 22°C. Following this procedure, ascorbic acid can be determined with a linear calibration graph up to 1.76 ng/mL and a detection limit of 0.28, based on 3S criterion. The relative error ranges between 6.77-1.66% for the concentration interval of ascorbic acid 1.76-17.61 ng/mL. The effects of certain foreign ions upon the reaction rate were determined for an assessment of the selectivity of the method. The method was applied for determination of ascorbic acid in pharmaceutical samples, and spectrophotometric method was used like an comparative method.

In the present study, a new sensitive and simple kinetic-spectrophotometric method for the determination of the insecticide diflubenzuron [1-(4-chlorophenyl)-3-(2,6-diflubenzoil)urea] is proposed. The method is based on the inhibited effect of diflubenzuron on the oxidation of sulphanilic acid (SA) by hydrogen peroxide in phosphate buffer in presence Cu(II) ion. Diflubenzuron was determined with linear calibration graph in the interval from 0.31 to 3.1 μg mL⁻¹ and from 3.1 to 31.0 μg mL⁻¹. The optimized conditions yielded a theoretical detection limit of 0.18 μg mL⁻¹ corresponding to 0.036 mg kg(-1)mushroom sample based on the 3S(b) criterion. The RSD is 5.03-1.83 % and 2.81-0.71 % for the concentration interval of diflubenzuron 0.31-3.1 μg mL⁻¹ and 3.1-31.0 μg mL⁻¹, respectively. The reaction was followed spectrophotometrically at 370 nm. The kinetic parameters of the reaction are reported, and the rate equations are suggested. The developed procedure was successfully applied to the rapid determination of diflubenzuron in spiked mushroom samples of different mushroom species. The HPLC method was used like a comparative method to verify results.