Scopul nostru este sprijinirea şi promovarea cercetării ştiinţifice şi facilitarea comunicării între cercetătorii români din întreaga lume.
Autori: Vlad Agotici, Ionel Ciucanu
Editorial: Studia Universitatis Babes-Bolyai, seria Chemia, 4, p.5-16, 2011.
The analysis of benzene, toluene and xylene by micro extraction
into a three phase extraction system (liquid-liquid-solid) followed by gas
chromatography is described. The analytes are extracted very fast into a
very small volume of organic solvent and simultaneously into a solid sorbent.
The efficiency of different solvents: dichloromethane, chlorophorm, carbon
tetrachloride, n-hexane and cyclohexane added to the sample in different
volumes used for liquid microextraction were evaluated. The best results were
obtained by using dichloromethane. The extracted quantity in the three phase
system was significantly higher than the usual two phase liquid-solid microextraction.
The RSD was between 11-12%, the linearity was very good (over 1 magnitude
order from 5 ng/mL to 6 mcg/mL) for all three compounds, the limits of detection
(S/N = 3) were in the ppb range and the recoveries between 84-96%. The working
conditions (extraction time, temperature, solvent, solvent volume, stirring rate) were
optimized. The optimum conditions for the extraction of all three analytes were
experimentally established for 200 mcL dichloromethane as organic phase, 25°C, at
a stirring rate of 400 rpm and 5 minutes extraction time. The developed method
was applied for the analysis of purposed compounds in wastewater samples
Cuvinte cheie: liquid-solid microextraction, liquid-liquid microextraction, liquidliquid-