1 research outputs found
Microfluidic Separation of Redox Reactions for Coulometry Based on Metallization at the Mixed Potential
Coulometric
detection of an analyte in a solution at nanoliter
scale was conducted by having redox reactions proceed simultaneously
on a platinum electrode. The analyte was oxidized on a part of the
electrode in one flow channel and silver was deposited on an array
of circular microelectrodes formed in another flow channel at a mixed
potential. Coulometric determination of the deposited silver showed
a steep change in the generated charge as a result of the complete
oxidation of silver. The short measurement time after the start of
the coulometry suppressed the increase in background charge, resulting
in significant lowering of the detection limit. The lower detection
limit for H<sub>2</sub>O<sub>2</sub> was 30 nM (3σ). To improve
selectivity and minimize the influence of coexisting interferents,
the shifting of the mixed potential, application of a permselective
membrane, and electrochemical elimination of the interferents were
effective modifications