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Volume 3, Issue 2
Insights in Analytical Electrochemistry
ISSN: 2470-9867
Analytical Chemistry-Formulation 2017
August 28-30, 2017
Page 31
8
th
Annual Congress on
&
14
th
International Conference and Exhibition on
August 28-30, 2017 Brussels, Belgium
Analytical and Bioanalytical Techniques
Pharmaceutical Formulations
Interrupted amperometry: A new ultrasensitive electroanalytical method
Daria V Navolotskaya
and
Sergey S Ermakov
Saint-Petersburg State University, Russia
I
nterrupted amperometry is a new technique for diffusion current measuring. The extremely high sensitivity is achieved due
to the special approach to the signal-to-noise ratio enhancement. Conventionally, the signal is associated with the diffusion
controlled faradaic current. Capacitive current is usually referred to the noise. In interrupted amperometry, capacitive current
is included in analytically useful part of the signal as well as faradaic current. Technically this is realized by adding a switcher to
the conventional electrical circuit for amperometric measurements. The switcher locks the circuit for the period of time tl and
then opens the circuit for the period of time to. Opening (or interrupting) and locking of the circuit are repeated periodically
during the entire experiment. The average measured current is defined as: I
m
= T/t
l
(I
d
+ ∑I
i
) where, T=t
l
+to is the period of
switching, I
d
is the diffusion current and Ii are interfering currents. If the T/t
l
ratio is of several orders, for example when tl=100
µs and T=100 ms, the measured current also exceeds the diffusion current for several orders. Analytical possibilities of the
proposed technique were investigated via direct determination of iron (III), Cd (II), Pb (II) ions, phenol and hydroquinone in
aqueous solutions; determination of dichromate ion in titration mode; and determination of oxygen using a Clark-type sensor.
Biography
Daria Navolotskaya completed PhD from Saint-Petersburg State University in 2013. She is currently working as a Senior Lecturer in the department of Analytical
Chemistry at the same institution.Professor Sergey Ermakov is the head of the department of analytical chemistry at Saint-Petersburg State University. He has
published more than 40 papers in reputed journals.
navolotskayadv@gmail.comDaria V Navolotskaya et al., Insights in Analytical Electrochemistry, 3:2
DOI: 10.21767/2470-9867-C1-002