Self-assembled sensor based on boron-doped diamond and its application in voltammetric analysis of picloram

A self-assembled sensor based on a boron-doped diamond was investigated as a sensitive tool for voltammetric analysis of a member of a pyridine herbicide family - picloram. A cyclic voltammetry and a differential pulse voltammetry were applied for investigation of the voltammetric behaviour and quantification of this herbicide. Picloram yielded one well-developed irreversible oxidation signal at a very positive potential about +1.5 V vs. Ag/AgCl/3 mol L-1 KCl electrode in an acidic medium and 1 mol L-1 H2SO4 was chosen as a suitable supporting electrolyte. Operating parameters of differential pulse voltammetry were optimized and the proposed voltammetric method provided a high repeatability (a relative standard deviation of 20 repeated measurements at a concentration level of picloram of 50 mu mol L-1 equaled to 2.58%), a linear concentration range from 2.5 to 90.9 mu mol L-1 and a low limit of detection (LD = 1.64 mu mol L-1). Practical usefulness of the 'environmentally-green' electrochemical sensor was verified by an analysis of spiked water samples with satisfactory recoveries.