Predicting electrophoretic mobility of beta-blockers in a water-methanol based electrolyte system

Summary Applicability of a mathematical model to predict the electrophoretic mobility of structurally related analyses is shown using generated mobility data for beta-blockers in a mixed aqueousmethanolic buffer. The mobilities of atenolol, alprenolol, labetalol and metoprolol in binary mixed solvent buffers containing different concentrations of methanol have been employed to train the model. Then the mobilities of propranolol, timolol and acebutalol have been predicted using the trained model. The produced mean prediction errors employing two and one experimental data points for three beta-blockers are 1.6 and 2.8%, respectively, which is easily within experimental uncertainty.     

A quantitative structure property relationship study of electrophoretic mobility of analytes in capillary zone electrophoresis

A quantitative structure property relationship (QSPR) is proposed to calculate the electrophoretic mobility of analytes in capillary zone electrophoresis. The proposed model employs logarithm of the electrophoretic mobility (ln micro) as dependent variable and partial charge (PQ), surface area (V(2/3)), total energy (TE), heat of formation (DeltaH(f)) and molecular refractivity (MR) as independent variables whose calculated using AM1 (Austin model 1) semi-empirical quantum mechanics method by HyperChem 7.0 software. The general form of the model is: ln micro =K(0)+K(1)PQ+K(2)V(2/3)+K(3)TE+K(4)DeltaH(f)+K(5)MR, where K(0)-K(5) are the model constants computed using a least-square method. The applicability of the model on real mobility data has been studied employing five experimental data sets of beta-blockers, benzoate derivatives, non-steroidal anti-inflammatory drugs, sulfonamides and amines in different buffers. The accuracy of the model is assessed using absolute average relative deviation (AARD) and the overall AARD value. The obtained AARD for the sets studied are 1.0 (N=10), 2.1 (N=26), 0.8 (N=11), 0.6 (N=13) and 2.7% (N=18), respectively, and the overall AARD is 1.4%. The model is cross-validated using one leave out technique and the obtained overall AARD is 1.8%. To further investigate on the applicability of the proposed model, the prediction capability of the model is evaluated by employing a minimum number of six experimental data points as training set, and predicting the mobility of other data points using trained models. The obtained overall AARD (for 48 predicted data points) is 5.6%.     

Silica-based mesoporous organic-inorganic nano-hybrid: a novel electroceramic nanomaterial for electroanalytical determination of selected cardiovascular drugs in human serum

Magnetic mesoporous silica was used for electrode modification and electro-oxidation of some cardiovascular drugs. The modified electrode was applied for detection of cardiovascular drugs using cyclic voltammetry, chronoamperometry, and differential pulse voltammetry. The modified electrode shows many advantages as an electrochemical sensor such as simple preparation method without using any specific electron transfer mediator or specific reagent, high sensitivity, excellent activity, short response time, long term stability and remarkable antifouling property toward for cardiovascular drugs and its oxidation product. Finally, the applicability of the sensor for determination of the selected drugs in human serum samples has been successfully demonstrated.     

Comments concerning “Study of solute–solvent and solvent–solvent interactions in pure and mixed binary solvents”

A number of mathematical equations representing the solute solubility in monosolvent and binary solvent mixtures are discussed. This work is a commentary to the article of Maitra and Baghchi that appeared in this journal.     

Solution thermodynamics and preferential solvation of triclocarban in {1,4-dioxane (1) + water (2)} mixtures at 298.15 K

The equilibrium solubility and preferential solvation of triclocarban in {1,4-dioxane (1) + water (2)} mixtures at 298.15 K was reported. Mole fraction solubility varies continuously from 2.85 × 10^–9 in neat water to 2.39 × 10^–3 in neat 1,4-dioxane. Solubility behaviour was adequately correlated by means of the Jouyban-Acree model. Based on the inverse Kirkwood-Buff integrals, preferential solvation parameters were calculated. Triclocarban is preferentially solvated by water in water-rich mixtures (0.00 < x₁ < 0.18) and also in 1,4-dioxane-rich mixtures (0.78 < x₁ < 1.00) but preferentially solvated by 1,4-dioxane in mixtures with similar solvent compositions.     

Equilibrium solubility,preferential solvation and apparent specific volume of sucrose in some {cosolvent (1) + water (2)} mixtures at 298.2 K

Sucrose is the most widely used sweetener in food and pharmaceuticals. Solubility data of this excipient in aqueous cosolvent mixtures is not abundant. Thus, the main objective of this research was to determine and correlate the equilibrium solubility of sucrose in some {cosolvent (1) + water (2)} mixtures at 298.2 K. Cosolvents were ethanol, propylene glycol and glycerol. Shaken flask method was used to determine isothermal solubility. Concentration measurements were performed by means of density determinations. Solubility of sucrose decreases non-linearly with the addition of cosolvent to water. By means of the inverse Kirkwood–Buff method it is shown that sucrose is preferentially solvated by cosolvent in water-rich mixtures but preferentially solvated by water in cosolvent-rich mixtures. Jouyban–Acree model correlates solubility values with the mixtures composition for all cosolvent systems. Moreover, apparent specific volume of sucrose was also calculated from density and compositions.     

Pre-concentration and quantification of aluminum in fish samples using a dispersive liquid–liquid micro-extraction–spectrofluorimetric method based on Al(III)–8-hydroxyquinoline complex’s fluorescence properties

A simple and fast dispersive liquid–liquid micro-extraction (DLLME)–spectrofluorimetric technique was developed and validated for the extraction and quantification of trace amounts of Al in fish samples, where 8-hydroxyquinoline was utilized as a spectrofluorimetric probe. In order to optimize the efficacy of the DLLME technique, the impact of experimental parameters on the extraction of Al(III) from fish samples was evaluated. Under the optimal conditions, the method was linear in the concentration range of 0.1–7.0 μg/g (r = 0.9996) with a LOD of 0.092 μg/g; additionally, the method was accurate (RE% of ? 3.0 to + 10.0%), precise (RSD% of 1.2–14.3%) and robust (RSD% of 3.8 and p value of 0.21) and its recovery was in the range of 97.0 ± 3.89–110.0 ± 12.5%; moreover, samples were stable before and during the analyses. Therefore, it can be claimed that the developed method could be successfully applied for the quantification of Al in fish samples.     

Preferential solvation of nifedipine in some aqueous co-solvent mixtures

Preferential solvation parameters of nifedipine (NIF) in ethanol (EtOH) + water and propylene glycol (PG) + water mixtures were obtained from their thermodynamic properties in solution using the inverse Kirkwood–Buff integrals. Preferential solvation parameter (δx_1,3) by both co-solvents is negative in the water-rich mixtures but positive in almost all the other compositions at 293.2, 303.2 and 313.2 K. Nevertheless, in EtOH-rich mixtures the values of δx_1,3 are also negative. It can be assumed that in water-rich mixtures the hydrophobic hydration around the non-polar groups of NIF plays a relevant role in the solvation. The higher drug solvation by co-solvent in mixtures of similar solvent proportions and in co-solvent-rich mixtures could be due mainly to polarity effects. Moreover, in these mixtures the drug could be acting as a Lewis acid with the co-solvents molecules. Finally, in EtOH-rich mixtures the drug could be acting as a Lewis base with water molecules.