Ferreira M. M. C., Antunes A. M., Volpe P. L. O., “A study of aminoacid transport through liquid membranes using UV-VIS spectroscopy”. Porsgrunn, Norway, 15-19/08/1999: 6th Scandinavian Symposium on Chemometrics (SSC6), Program & Abstracts, 52 (1999). Oral L34.
A study of aminoacid transport through liquid membranes
using uv-vis
spectroscopy
Márcia M. C. Ferreira, Alexandre M. Antunes
& Pedro L. O. Volpe
Instituto de Química - Univesidade Estadual
de Campinas UNICAMP, CAMPINAS - SP -
13083-970 BRAZIL marcia@iqm.unicamp.br
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
for characterization of real complex systems.
Diffusion of mixtures of three aminoacids through a hydrophobic
liquid membranes is studied in
the present work. The transport of some species through
a liquid membrane occurs only in the
presence of appropriate carrier. The most used technique
in such cases is the "bulk liquid
membrane". In this work we report the transport of Phenylalanine
(Phe), Tyrosine (Tyr) and
Tryptophan (Trp) through a chloroform liquid membrane
containing Aerosol OT (sodium bis-
2-(ethyl hexyl) sulfossuccinate). The transport can be
monitored by recording UV-Vis spectra at
the receiving phase, withing small time intervals during
the transport process, taken with a diode-
array spectrometer.
The transport of 4 mixtures of Phe, Tyr and Trp in a buffer
solution (pH 1.5) was followed for 30
minutes, taking UV-Vis spectra (HP 8452 A with cell flux)
withing one minute interval. The
apparatus used consisted of a U cell, having as source
phase the buffer solution, chloroform
containing AOT reverse micelles ([AOT]=10 mmol L-1)
as the liquid membrane and a buffer
solution at pH 9 as receiving phase.
The data set consists of 12 spectra taken from 245 - 310
nm with 1 nm interval (X=66x13) for
each sample. The trilinear decomposition (TLD) chemometric
method for 3D data (wavelength,
time and intensities) was used to solve the kinetic curves
for the compounds. The ordinary least
square (OLD) method was applied separately to each mixture
using pure experimental spectra.
The kinetic profiles are very similar to those obtained
by TLD. The transport rates, which are
given by the slope of the kinetic curves, were calculated
using OLS and TLD concentrations.
It can be concluded that TLD is a good option for the
study of this transport phenomenon.
52