Ferreira M. M. C., Antunes A. M., Melgo M. S., Volpe P. L. O., “Potassium diffusion through liquid membranes using spectral and chemometric methods”.  Prague, Czech Republic, 23-28/08/1998: XXIV European Congress on Molecular Spectroscopy (EUCMOS XXIV), Book of Abstracts, 115 (1998). Poster D116.

EUCMOS XXIV, Prague 1998 (Book of Abstracts)

D116

POTASSIUM DIFFUSION THROUGH LIQUID MEMBRANES USING
SPECTRAL AND CHEMOMETRIC METHODS


M. M. C. Ferreira,  A. M. Antunes, M. S. Melo and P. L. O. Volpe

Instituto de Química - Universidade Estadual de Campinas   UNICAMP
CAMPINAS - SP - 13083-970   BRAZIL
 
 

             Simultaneous determination of  closely related species  is  of  continuing interest in
chemistry.   Modern  instruments  like  spectrometers  with  diode-array  detector  and   fast
computers generate several spectra in a short period of time.  All this data can be analyzed
by the  use of chemometrics in  the characterization of  real complex systems.
             In this study,  the  diffusion of potassium through a hydrophobic liquid membrane is
studied using mixtures of  three  salts.   The  transport  of  some  species  through  a  liquid
membrane occurs only in  the presence of appropriate carrier  (to achieve its solubilization).
The  most used technique  in such  cases is the  "bulk liquid membrane".   In  this  work the
transport mechanism is called symport, and the anionic species is carried through  together
with the cation.  The cation transport  in this situation  can  be monitored  by  recording  the
anion UV-Vis  spectra  taken with  diode-array  detector,  in  small time intervals  during  the
process.
            The  transport  of  4  mixtures  of  2-nitrophenolate,  2,4-dinitrophenolate  and   2,5-
dinitrophenolate salts in a buffer solution (pH 12)  was followed for 90 minutes,  taking UV-
Vis  spectra  (HP 8452 A  with cell flux)  within  five minutes  interval.   The apparatus used
consists of a  U  cell,  having  as source phase  the  buffer  solution,  chloroform containing
crown ether  18C6  as the liquid membrane and  distilled  water  as  receiving  phase.
           The data set to be analyzed  consists of  18  spectra taken from  190 - 820 nm  with
2 nm interval (X=316´18) for each sample. The trilinear decomposition (TLD)  chemometric
method for  3D  data  (wavelength,  time  and  intensities)  is  a powerful  method  for curve
resolution  (qualitative)  and also for quantitative analysis.   The  TLD  results  are the pure
spectra  of the three  pure compounds  (2-np,  2,4-dnp  and  2,5-dnp),  besides  the  kinetic
curves,  from which  the transport rates are  obtained.
 
 


 

[FAPESP, CNPq]
 
 

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