Study of mass transfer in a dynamic hollow-fibreliquid phase microextraction system

• The extraction characteristics of a dynamic hollow-fibre liquid phase microextractionsystem were investigated by studying the mass transfer and diffusion rates of dinitrophenolsfrom plasma samples over the liquid membrane (dihexylether). The measureddiffusion coefficients were compared with theoretical values calculated from Stokesdiameters. The diffusion mechanism was simulated by computer and the most polarcompounds, 2,4-dinitrophenol and 4,6-o-dinitrocresol, had associated diffusion coefficientsthat were close to the calculated theoretical values. 2-sec-Butyl-4,6 dinitrophenoland 2-tert-butyl-4,6-dinitrophenol, the compounds with the highest log P values, wereretained by the polypropylene membrane, which reduced the experimentally observeddiffusion rates to about half of the theoretical values. The retention was most likely due todispersive forces interacting with the pore inner walls. Extraction was linearly correlatedwith time for all compounds and the repeatability was high (RSDs 7–11%), even for theshortest extraction times. Method LOD as the amount injected ranged between 0.3 and3.1 ng for an extraction cycle of 213 s.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Andra medicinska och farmaceutiska grundvetenskaper (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Other Basic Medicine (hsv//eng)

Nyckelord

dynamic hollowfibre liquid phase microextraction

Chemistry

Kemi

Analytical Chemistry

analytisk kemi

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