Voltammetric Determination of Nitrofurantoin at a Mercury Meniscus Modified Silver Solid Amalgam Electrode
Abstrakt
Electrochemical behavior of nitrofurantoin (NF) was studied by direct current voltammetry (DCV), differential pulse voltammetry (DPV), and cyclic voltammetry (CV) using a mercury meniscus modified silver solid amalgam electrode (m-AgSAE). Voltammetric behavior of NF was studied in cathodic region of potentials in dependence on pH. pH 7.0 was selected as an optimal medium for the determination of NF by both DCV and DPV, with the optimal methanol-water volume ratio of 1 : 9.
In order to reduce the negative influence of electrode passivation, the suitable regeneration potentials were found (0 mV and -900 mV). The optimal conditions were found for the determination of NF in concentration ranges from 6 x 10(-6) mol L-1 to 1 x 10(-4) mol L-1 using DCV technique, and from 2 x 10(-7) mol L-1 to 1 x 10(-4) mol L-1 using DPV technique, both in the medium of methanol-Britton-Robinson buffer pH 7.0 (1 : 9).
The attained limit of quantification (LOQ) of NF was 1.6 x 10(-6) mol L-1 for DCV and 8.1 x 10(-8) mol L-1 for DPV. The practical applicability of the newly developed DPV method was verified by direct determination of NF in model samples of drinking and river water, with LOQs 2.2 x 10(-7) mol L-1 and 2.5 x 10(-7) mol L-1, respectively.