Article

Kinetic determination of morphine by means of Bray-Liebhafsky oscillatory reaction system using analyte pulse perturbation technique.

Faculty of Pharmacy, Department of Physical Chemistry, University of Belgrade, Vojvode Stepe 450, YU-11000 Belgrade, Serbia and Montenegro. <>
Analytica chimica acta (Impact Factor: 4.31). 02/2007; 582(2):367-74. DOI: 10.1016/j.aca.2006.09.026
Source: PubMed

ABSTRACT A novel kinetic method for micro-quantitative determinations of morphine (MH) is proposed and validated. The method is based on the potentiometric monitoring of the concentration perturbations of the oscillatory reaction system being in a stable non-equilibrium stationary state close to the bifurcation point between stable and oscillatory state. The response of the Bray-Liebhafsky (BL) oscillatory reaction as a matrix system, to the perturbations by different concentrations of morphine, is followed by a Pt-electrode. The proposed method relies on the linear relationship between maximal potential shift, DeltaE(m), and the logarithm of the added morphine amounts in the range of 0.004-0.18 micromol. Under optimum conditions, the sensitivity of the proposed method (as the limit of detection) is 0.001 micromol and the method is featured by good precision (R.S.D.=1.6%) as well as the excellent sample throughput (45 samples h(-1)). In addition to standard solution analysis, this approach was successfully applied for quantitative determination of morphine in a typical pharmaceutical dosage form. Some aspects of the possible mechanism of morphine action on the BL oscillating chemical system are discussed in detail.

0 Bookmarks
 · 
111 Views
  • Source
  • [Show abstract] [Hide abstract]
    ABSTRACT: A hybrid of reduced graphene oxide-palladium (RGO-Pd) nano- to submicron-scale particles was simultaneously chemically prepared using microwave irradiation. The electrochemical investigation of the resulting hybrid was achieved using cyclic voltammetry and differential pulse voltammetry. RGO-Pd had a higher current response than unmodified RGO toward the oxidation of morphine. Several factors that can affect the electrochemical response were studied, including accumulation time and potential, Pd loading, scan rate, and pH of electrolyte. At the optimum conditions, the concentration of morphine was determined using differential pulse voltammetry in a linear range from 0.34 to 12 μmol L(-1) and from 14 to 100 μmol L(-1), with detection limits of 12.95 nmol L(-1) for the first range. The electrode had high sensitivity toward morphine oxidation in the presence of dopamine (DA) and of the interference compounds ascorbic acid (AA) and uric acid (UA). Electrochemical determination of morphine in a spiked urine sample was performed, and a low detection limit was obtained. Validation conditions including reproducibility, sensitivity, and recovery were evaluated successfully in the determination of morphine in diluted human urine.
    Analytical and Bioanalytical Chemistry 07/2014; · 3.66 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A new and convenient method for the determination of Alizarin Red S by the perturbations caused by different amounts of Alizarin Red S on a novel B-Z oscillating system is proposed. This new type Belousov-Zhabotinskii involves a macrocyclic copper(II) complex [CuL](ClO4)2 as catalyst and malic acid as the substrate. The ligand L in the complex is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. It is found that the relationship between the change in the oscillation amplitude and the logarithm of the Alizarin Red S concentration in the range of 1.5 × 10−7 to 1 × 10−3 M fits a polynomial model: ΔA = 659 + 184.2 log [Alizarin Red S]+ 12.9 log2 [Alizarin Red S]. The RSD obtained with ten samples is 4.4%. The probable mechanism involving the perturbation of Alizarin Red S on the oscillating chemical system is also discussed.
    Central European Journal of Chemistry 7(3):291-297. · 1.17 Impact Factor

Full-text (3 Sources)

View
22 Downloads
Available from
Jun 3, 2014

View other sources