A simple spectrophotometric method has been described for the determination of thiamine. The method is based on the precipitation of sulphur as barium sulphate using barium chloride after oxidation of thiamine by sodium hydroxide and hydrogen peroxide. Beer's law was obeyed over the concentration range from 2-32 µg/mL thiamine. The average of standard deviation was 1.18×10 -2 ; standard error, 5.20×10 -3 ; relative standard deviation, 0.51%; relative standard error, 5.40×10 -3 ; 95% coefficient, 1.48×10 -2 ; the limit of detection, 0.41 µg/mL; the limit of quantification, 1.38 µg/mL and recovery, 100.03% thiamine. Finally, the developed method was applied to the determination of thiamine in pharmaceutical formulations.Thiamine Oxidation Precipitation Determination Barium sulphate Spectrophotometric
ABSTRACT:A new, simple, fast and sensitive two spectrophotometric methods has been developed for determination of Escitalopram in bulk and tablet dosage forms. The method A is based on the oxidation of Escitalopram by a known excess of bromate-bromide mixture in hydrochloric acid medium, reduction of the residual oxidant by a fixed amount of iron(II) and the formation of iron(III)-thiocyanate-complex which is measured at 480 nm. In the method B, 1,10-phenanthroline is used as a complexing agent and the formation of iron(II)-1,10-phenanthroline, which is measured at 510 nm. The methods obeys Beer's law in the concentration range of 0.5 -8.0 µg mL -1 and 0.5-6.5 µg mL , respectively. The methods have been successfully applied to the determination of Escitalopram in pure and dosage forms.
This study reports the adsorption of malachite green (MG) dye by Seeds of Dates (SD) from solution. Batch adsorption of MG was conducted to evaluate the effect of initial pH, contact time, temperature, initial dye concentration, SD adsorbent dose, and removal of the adsorbate MG dye from aqueous solution to understand the mechanism of adsorption involved. Adsorption equilibrium reached rapidly with 96% MG removal in 120 min. Fit of the adsorption experimental data was tested on the pseudo-first and pseudo-second-order kinetics mathematical equations, which was noted to follow the pseudo-second-order kinetics better, with coefficient of correlation ≥0.992. The equilibrium process was well described by the Freundlich isotherm model, with maximum adsorption capacity of 158.98 mg g −1 . The study shows that SD has the potential of application as an efficient sorbent for the removal of MG from aqueous solutions.
This study explored the adsorption behavior of Cd(II) ions on Junipers Procera Roots powder from aqueous solutions. The effect of various operational parameters such as pH, contact time, initial adsorbate concentration, dosage of adsorbent and temperature on adsorption of Cd(II) ions were investigated using batch adsorption experiments. The optimum pH for Cd(II) adsorption was found to be 7.0. The suitability of Langmuir and Freundlich adsorption models to the equilibrium data was investigated. The adsorption was well described by the Freundlich isotherm model indicating the presence of heterogeneous sites for Cd(II) adsorption. Thermodynamic parameters showed that the adsorption of Cd(II) on Junipers Procera Roots was feasible, spontaneous and exothermic.
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