Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 2, pp. 267−270.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
N.M. Chezhina, S.S. Ermakov, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 2, pp. 273−276.
AND CORROSION PROTECTION OF METALS
Fast Procedure for No-Reference Inversion-Voltammetric
Determination of Lead in Aqueous Solutions
N. M. Chezhina and S. S. Ermakov
St. Petersburg State University, St. Petersburg, Russia
Received June 18, 2008
Abstract—Possibility of no-reference inversion-voltammetric determination of lead in aqueous solutions with the
use of a preliminarily determined coulometric constant of the electrochemical cell, which enables substantially
faster analysis as compared with the known analogs, was studied. The coulometric constants of electrochemical
cells with a mercury film electrode were found for different solution volumes.
Reliable and easily automated analytical techniques
are necessary for controlling the quality of products and,
in particular, the quality of plated coatings and products
of hydrometallurgical industries. To such methods
belong no-reference electrochemical techniques. This
communication considers a version of methods of this
Several alternatives of no-reference inversion-voltam-
metric methods have been suggested. To these techniques
belongs no-reference inversion chronopotentiometry
 based on multiple-cycle dissolution of a metal from
an amalgam produced in the pre-electrolysis stage and
subsequent determination of the quantity of electricity,
, necessary for complete recovery of a substance from
solution. In addition, a variation of the no-reference method
based on cyclic deposition and dissolution of a metal from
the amalgam obtained in the accumulation stage has been
suggested, named “dynamic coulometry” .
The aboveprocedures of no-reference electrochemical
methods were not further developed and have failed
to ﬁ nd wide application because of the comparatively
intricate and prolonged analytical procedures involved
and need to use specialized instruments. The prolonged
analysis is also characteristic of an integrated no-reference
electrochemical method [3, 4] combining principles of
inversion voltammetry (IVA) and controlled-potential
coulometry (CPC), based on a calculation of the total
quantity of electricity, Q
, by the Meites formula .
However, three successive measurements with different
accumulation times t
should be made to find Q
making the analysis duration substantially longer than
that in the classical IVA procedure.
To develop the previously proposed approach to no-
reference determination of lead ions, it was suggested in
this study to solve this problem by using the following
equation for calculation:
is the quantity of electricity consumed for
conversion of a given substance during a time t; t, pre-
electrolysis duration; and k, coulometric constant of the
electrochemical cell .
Use of formula (1) can simplify the measurement
scheme, because a single determination of the quantity of
, corresponding to an accumulation time t
is sufﬁ cient in this case. However, its practical application
requires a preliminary determination of the coulometric
constant k. The value of this constant is determined by
the measurement conditions and can be theoretically
calculated by the equation
where S is the surface area of the working electrode; D,
diffusion coefﬁ cient; V, solution volume; and δ, diffusion