Boron‐Doped Diamond Electrode Coupled to Liquid Chromatography: Application to Simultaneous Determination of Benzodiazepines

Abstract

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 RP18 column (250 Â 4.6 mm, 5 mm) with a mobile phase sodium phosphate (pH 3.5; 0.10 mol L . 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 À 1.9 V as initial potential. The method presented linearity, repeatability and ruggedness and it represents a novel, alternative electroanalytical method for benzodiazepines determination.

Thin‐Layer and Wall‐Jet Arrangement of Amperometric Detector with Boron‐Doped Diamond Electrode: Comparison of Amperometric Determination of Aminobiphenyls in HPLC‐ED

“…Several types of laboratory-made flow-through detection cells have been designed for this purpose mostly with electrodes in wall-jet [10][11][12][13] or thinlayer [14,15] arrangements. Further, commercial thinlayer flow cells (Bioanalytical System and ESA, both USA) were adapted for BDD electrodes [16,17]. In our laboratory, a pen-type BDD disk electrode was designed [2] and successfully used for voltammetric determination of 2-aminobiphenyl (2-AB), 3-aminobiphenyl (3-AB), and 4-aminobiphenyl (4-AB) [18], 3-nitrofluoranthene and 3-aminofluoranthene [19], and phenolic compounds in foods [13]; in the latter study this electrode was also employed in laboratory-made wall-jet amperometric detection cell.…”

Analytical Applications of Electrochemically Pretreated Boron‐Doped Diamond Electrodes

“…Conventionally, in many cases the CPT is preceded by an APT to clean the BDDE surface, oxidizing any strongly adsorbed organic contaminant . For example, the electroanalytical determination of the herbicide picloram was carried out using a CPT‐BDDE, whose pretreatment was always preceded by an APT; the CPT or APT involved polarizations at −2.0 V or +2.0 vs .…”

Electrochemical Detection of Benzodiazepines, Following Liquid Chromatography, for Applications in Pharmaceutical, Biomedical and Forensic Investigations

“…Both Hg and carbon based working electrodes have been employed successfully for benzodiazepine determination in complex samples such as blood, milk and tissue. More recently, Martins et al [54] have reported on the determination of diazepam, clonazepam, flunitrazepam and nitrazepam using boron doped diamond electrode (BDDE), as part of a liquid chromatographic system. Cyclic voltammetry was employed to investigate the electrochemical behaviour of the four benzodiazepines at the BDDE in 0.1 M phosphate buffer at pH 3.5, 6.0 and 8.0 with the optimum response obtained at pH 3.5.…”