Reagentless Acid−Base Titration for Alkalinity Detection in Seawater
Fecha
2021Disciplina/s
FarmaciaResumen
Herein, we report on a reagentless electroanalytical
methodology for automatized acid−base titrations of water samples
that are confined into very thin spatial domains. The concept is
based on the recent discovery from our group (Wiorek, A. et al.
Anal. Chem. 2019, 91, 14951−14959), in which polyaniline
(PANI) films were found to be an excellent material to release a
massive charge of protons in a short time, achieving hence the
efficient (and controlled) acidification of a sample. We now
demonstrate and validate the analytical usefulness of this approach
with samples collected from the Baltic Sea: the titration protocol
indeed acts as an alkalinity sensor via the calculation of the proton
charge needed to reach pH 4.0 in the sample, as per the formal
definition of the alkalinity parameter. In essence, the alkalinity
sensor is based on the linear relationship found between the released charge from the PANI film and the bicarbonate concentration
in the sample (i.e., the wa...