The Natural Diatomite from Caldiran-Van (Turkey): Electroanalytical Application to Antimigraine Compound Naratriptan at Modified Carbon Paste Electrode

This paper is the first report describing the characterization of local diatomite of Caldiran-Van region (Eastern Anatolia, Turkey). Special attention was paid to the ability of its electroanalytical performance at modified electrodes and to the potential application of diatomite-modified electrode. For this purpose, the determination of Naratriptan which is a novel oral triptan (5-hydroxytryptamine receptor agonist) in migraine treatment, by means of a carbon paste electrode modified with 10% (w/w) of diatomite was studied using cyclic and square-wave voltammetry. The experimental conditions that affect the electrode reaction process were studied in terms of pH of the supporting electrolyte, scan rate, accumulation variables, modifier composition and square-wave parameters. Using square-wave stripping mode, the drug yielded a well-defined voltammetric response in Britton-Robinson buffer, pH 4.0 at 0.84 V (vs Ag/AgCl) (a preconcentration step being carried out with an open circuit at 120 s). The process could be used to determine Naratriptan concentrations in the range 5x10-7-9x10-7 M, with a detection limit of 1.25x10-7 M (46.5 μg L-1). The applicability of the method to spiked human urine samples was illustrated.