Biomedical Engineering Reference
In-Depth Information
(
A
)
(
B
)
Figure 13.9
Scheme of measuring arramgement (A), where: 1 - injector, 2 - probe, 3 - Pt
electrode, 4 - Ag/AgCl electrode, 5 -analyzed surface, 6 - contact to analyzed surface and
surface modii cation (B).
with water, dried and their radioactivity was measured. h e experimental
set-up used to investigate the conductance of the layer on the electrode sur-
face consisted of a potentiostat, a l ow injection electrochemical cell and an
X-Y recorder. h e tel on probe with injector and saturated Ag/AgCl reference
electrode was used for realization of the l ow injection electrochemical cell.
h is construction allows the liquid analyte around the electrode surface to be
changed rapidly. h e probe working surface is about 0.75 cm
2
. Measurements
were performed with tris-HCl buf er solution as the background electrolyte.
Solutions with concentrations of 100 mg/l Phe were achieved by addition of
the corresponding substances to the background electrolyte. h e working
electrode was controlled at +0.9 V (respectively to Ag/AgCl RE).
h e ei cacy of this approach was coni rmed by the analysis of the sili-
con plates treated with silane in the presence of adenosine (A), AMP, ATP
and TTP on their sorption ability for P
32
ATP. h e “ATP-modii ed” plates
had a high selectivity for their substrate-template. h e sorbtion of leucine,
methionine and phenylalanine is largest for the surfaces modii ed with the
corresponding amino acid template.
h e dif erence in specii c sorption of phenylalanine and leucine by the
sample modii ed with leucine is not very large. Also, the specii c sorp-
tion of phenylalanine by Phe- and Leu-modii ed samples is very similar.
It cannot be related to the homologous structure of the molecules such as
phenylalanine and leucine. Probably, the sorption of molecules on the tem-
plate sites is an integral value governed by molecular shape and structure
and by the interaction between the functional groups of site structure and
sorbet molecules.
h e sorption of cholesterol on electrodes modii ed with silane in the
presence of cholesterol leads to the surface monomolecular layer being
