VOLTAMMETRIC USE OF A GRAPHITE ELECTRODE MODIFIED WITH OV-17 SILICONE FOR THE DETERMINATION OF ORGANIC-COMPOUNDS

The use of a graphite electrode modified with OV-17 silicone (a stationary phase material used in gas chromatographic columns) is described. The procedure is based on preconcentration of the compounds to be assessed in an open circuit in Britton-Robinson buffer (pH 4) with mechanical stirring (550 rpm) and uses a modified electrode at a silicone to graphite ratio of 40:60 and a 10-min accumulation time. Measurements are performed in Britton-Robinson buffer (pH 7) using differential-pulse voltammetry with a scan rate of 7.5 mV s-1 and a pulse amplitude of 100 mV. Under these experimental conditions, a detection limit for benomyl of 6.9 ng ml-1 can be achieved with a relative error of 6%.