title: Bell-shaped extraction device assisted liquid-liquid microextraction technique and its optimization using response-surface methodology.
abstract: We have developed a new microextraction technique for equilibrium, non-exhaustive analyte preconcentration from aqueous solutions into organic solvents lighter than water. The key point of the method is application of specially designed and optimized bell-shaped extraction device, BSED. The technique has been tested and applied to the preconcentration of selected volatile and semi volatile compounds which were determined by gas chromatography/mass spectrometry in spiked water samples. The significant parameters of the extraction have been found using chemometric procedures and these parameters were optimized using the central composite design (CCD) for two solvents. The analyte preconcentration factors were in a range from 8.3 to 161.8 (repeatability from 7 to 14%) for heptane, and 50.0-105.0 (repeatability from 0 to 5%) for tert-butyl acetate. The reproducibility of the technique was within 1-8%. The values of limits of detection and determination were 0.1-3.3 ng mL(-1) for heptane and 0.3-10.7 ng mL(-1) for tert-butyl acetate. The new microextraction technique has been found to be a cheap, simple and flexible alternative to the common procedures, such as SPME or LLME. This BSED-LLME technique can also be combined with other separation methods, e.g., HPLC or CE.
authors.affiliation: Charles University in Prague, Faculty of Science, Department of Analytical Chemistry, Albertov 6, 128 43 Prague 2, Czech Republic. cabala@natur.cuni.cz
authors.forename: Radomír
authors.initials: R
authors.lastname: Čabala
authors.forename: Miroslava
authors.initials: M
authors.lastname: Bursová
mesh_terms: D060766:Drinking Water / Q000032:analysis; D004867:Equipment Design; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D059627:Liquid Phase Microextraction / Q000295:instrumentation* / Q000379:methods; D008900:Mineral Waters / Q000032:analysis; D015203:Reproducibility of Results; D014867:Water / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D060766:Drinking Water; D008900:Mineral Waters; D014874:Water Pollutants, Chemical; D014867:Water