Ioana Diaconu

Transport of p-Nitrophenol through an Agitated Bulk Liquid Membrane

The transport of p-nitrophenol (PNP) through an agitated bulk liquid membrane (ABLM) was investigated. A kinetic model of two consecutive irreversible first order reactions was applied in order to describe pertraction. The influence of PNP concentration in the feed solution, NaOH concentration in the stripping phase, and the type of solvent on the transport parameters (k′ f , k′ s , t max, , J max) was studied. To describe transport kinetics, the apparent mass transfer coefficient (k′ [cm/s]) as a parameter independent of volume and a membrane area was proposed. The results indicated that pertraction efficiency decreases in the series: benzene > toluene > p-xylene. In the investigated range of concentrations, the influence of the feed phase concentration (PNP) on pertraction efficiency is much higher than the stripping phase concentration (NaOH). It was also found that pertraction is controlled by PNP diffusion and sorption (extraction) at the feed/liquid membrane interface. The average value for the overall mass transfer coefficient is equal to 3.564(±0.047) × 10−4 cm/s which is characteristic for the studied system.

Analytical Applications of Transport Through Bulk Liquid Membranes

ABSTRACT This review discusses the results of research in the use of bulk liquid membranes in separation processes and preconcentration for analytical purposes. It includes some theoretical aspects, definitions, types of liquid membranes, and transport mechanism, as well as advantages of using liquid membranes in laboratory studies. These concepts are necessary to understand fundamental principles of liquid membrane transport. Due to the multiple advantages of liquid membranes several studies present analytical applications of the transport through liquid membranes in separation or preconcentration processes of metallic cations and some organic compounds, such as phenol and phenolic derivatives, organic acids, amino acids, carbohydrates, and drugs. This review presents coupled techniques such as separation through the liquid membrane coupled with flow injection analysis.

Facilitated transport of 5-aminosalicylic acid through bulk liquid membrane

This paper describes the experimental results obtained at the transport of 5-aminosalicylic acid (5ASA) through agitated bulk liquid membrane, using Aliquat 336, as carrier, dissolved in a chloroform membrane. The influence of 5-aminosalicylic acid concentration in the feed source, HCl concentration in the stripping phase and carrier (Aliquat 336) concentration in the membrane were investigated. The optimal pH condition of feed source was established based on the speciation diagram of 5-aminosalicylic acid. The assessment of the transport process was performed by determining the kinetic parameters—mass transfer coefficient and entrance and exist flow in and out of the chloroform membrane.

Estimation of Uncertainty for Measuring Codeine Phosphate Tablets Formulation Using UV-Vis Spectrophotometry

Analytical results represent a very important part in a quality control program. Uncertainty estimation is an important step in method validation. The objective of this paper is to study the uncertainty of measurement estimation in the quantitative determination of codeine phosphate from pharmaceutical formulations using UV-VIS spectrophotometry. The uncertainty estimation was performed using the Ishikawa diagram. The estimation of uncertainty components proved to be a good way for the experimental model to obtain low contribution of uncertainty to the analytical result.

Transport and separation through bulk liquid membrane of some biologic active compounds

Abstract Transport through liquid membranes of various chemical species is a viable method for different applications in analytical or technological domain. This paper presents the transport and separation results of two compounds of pharmaceutical importance: salicylic acid and aspirin, using bulk liquid membrane technique. We studied the effect of the feed source and receiving phase pH on the transport efficiency of the two compounds throught chloroform membrane. These results were correlated with speciation diagrams of salicylic acid and aspirin. The speciation diagrams shows that in these pH conditions, for aqueous phase of the membrane system, the two compounds are mostly undissociated form and therefore active for transport. In this system it can be achieve separation of the two compounds, salicylic acid and aspirin, using a suitable complexing agent in the feed source such as Fe3+. In this way salicylic acid forms an inactive complex structure for transport while aspirin crosses the membrane and it is recovered in a percentage of 80% in the receiving phase membrane system.