Fruits and vegetables constitute the cheapest source of essential trace elements for the majority of people living in developing countries. The Cu, Fe and Zn contents in twenty selected wine samples produced in the South-East region of Serbia were determined by flame atomic absorption spectrometry. The Cu concentrations varied from 0.07 to 0.57 ppm in wines, and the Fe concentrations fluctuated from 2.93 to 36.2 ppm, while the Zn levels were in the range from 0.21 to 0.67 ppm. The established contents of Cu and Zn showed that wines from this part of the world could serve as good dietary sources of the essential trace metals, and the determined values were within the allowed metals levels in wines for human consumption.

No abstract

An accurate, sensitive and reproducible high performance liquid chromatographic (HPLC) method for the quantification of doxycycline hyclate in pharmaceutical samples has been developed and validated. The drug and the standard were eluted from a Lichrosorb RP-8 (250 mm×4.6 mm, 10 µm particle size) at 20 °C with a mobile phase consisting of methanol, acetonitrile and 0.010 M aqueous solution of oxalic acid (2:3:5, v/v/v). The flow rate was 1.25 ml min -1 . A UV detector set at 350 nm was used to monitor the effluent. Each analysis required no longer than 4 min. The limits of detection and quantification were 1.15 and 3.84 µg ml -1 , respectively. Recoveries for different concentrations ranged from 99.58 to 101.93 %.

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...

The aim of this work was to develop a new kinetic spectrophotometric method for the determination of ibuprofen in pharmaceutical formulations. Ibuprofen was determined in an acidic ethanolic medium by monitoring the rate of appearance of 1-nitroso-2-naphthol, resulting from the displacement by ibuprofen of Co(III) from the tris(1-nitroso-2-naptholato)cobalt(III) complex. The optimum operating conditions regarding reagent concentrations and temperature were established. The tangent method was adopted for constructing the calibration curve, which was found to be linear over the concentration range 0.21-1.44 and 1.44-2.06 g ml -1 . The optimized conditions yielded a theoretical detection limit of 0.03 g ml -1 based on the 3.3 S 0 criterion. The interference effects of the usual excipients of powdery drugs, foreign ions and amino acids on the reaction rate were studied in order to assess the selectivity of the method. The developed procedure was successfully applied for the rapid determination of ibuprofen in commercial pharmaceutical formulations and human control serum. The unique features of this procedure are that the determination can be performed at room temperature and the analysis time is short. The newly developed method is simple, inexpensive and efficient for use in the analysis of a large number of samples.