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Advisor(s)
Abstract(s)
The electrochemical behaviour of the pesticide
metam (MT) at a glassy carbon working electrode (GCE)
and at a hanging mercury drop electrode (HMDE) was
investigated. Different voltammetric techniques, including
cyclic voltammetry (CV) and square wave voltammetry
(SWV), were used. An anodic peak (independent of pH) at
+1.46 V vs AgCl/Ag was observed in MTaqueous solution
using the GCE. SWV calibration curves were plotted under
optimized conditions (pH 2.5 and frequency 50 Hz), which
showed a linear response for 17–29 mg L−1. Electrochemical
reduction was also explored, using the HMDE. A well
defined cathodic peak was recorded at −0.72 V vs AgCl/
Ag, dependent on pH. After optimizing the operating conditions
(pH 10.1, frequency 150 Hz, potential deposition
−0.20 V for 10 s), calibration curves was measured in the
concentration range 2.5×10−1 to 1.0 mg L−1 using SWV.
The electrochemical behaviour of this compound facilitated
the development of a flow injection analysis (FIA)
system with amperometric detection for the quantification
of MT in commercial formulations and spiked water samples.
An assessment of the optimal FIA conditions indicated
that the best analytical results were obtained at a
potential of +1.30 V, an injection volume of 207 μL and
an overall flow rate of 2.4 ml min−1. Real samples were
analysed via calibration curves over the concentration
range 1.3×10−2 to 1.3 mg L−1. Recoveries from the real
samples (spiked waters and commercial formulations) were
between 97.4 and 105.5%. The precision of the proposed
method was evaluated by assessing the relative standard
deviation (RSD %) of ten consecutive determinations of
one sample (1.0 mg L−1), and the value obtained was 1.5%.
Description
Keywords
Metam Glassy carbon electrode Hanging mercury drop electrode Flow injection amperometric system
Citation
Publisher
Springer-Verlag