Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The applicability of boron-doped diamond (BDD) as a working electrode in an amperometric cell, coupled to HPLC, was demonstrated, for determining benzodiazepines in pharmaceutical preparations. The separation of the benzodiazepines was achieved using a Waters XTerra RP 18 column (250 x 4.6 mm, 5 mu m) with a mobile phase sodium phosphate (pH 3.5; 0.10 mol L(-1))-acetonitrile (65:35, v/v) at flow of 1.2 mL min(-1). The measurements were performed in a system 871 Advanced Bioscan (Metrohm) with a BDD (8000 ppm) adapted to the thin layer mode cell. Stainless steel and platinum wire were used as reference and auxiliary electrodes, respectively. The cell was operated in pulse mode, using -1.9 V as initial potential. The method presented linearity, repeatability and ruggedness and it represents a novel, alternative electroanalytical method for benzodiazepines determination.224455462Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)