TECHNOLOGY FOCUS - ELECTRONICS - Preferred Electrode: The electrode is a disc electrode, a microelectrode or a band electrode, where the disc electrode is of diameter of 100 nm to 2 mm, the band electrode is rectangular and each side is of length (100 nm to 2 cm), and the microelectrode is of diameter ( less than or equal to 50 mu m). The metal nanoparticle-modified boron-doped diamond is at least partly insulated, where the metal nanoparticle-modified boron-doped diamond is insulated using an insulator selected from: glass, polytetrafluoroethylene, polypropylene, porcelain, polyethylene, polyvinyl chloride, silicone, and/or ethylene tetrafluoroethylene.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The acid is a strong acid, where the acid is saturated with electrolyte, and the electrolyte comprises potassium nitrate. The acid comprises an acid selected from sulfuric acid, nitric acid or perchloric acid (preferably concentrated sulfuric acid). The boron-doping level in the boron-doped diamond is 1x 1019 to 5|asterisk1020 boron atoms cm-3. The boron-doped diamond has a hydrophilic front surface, where the hydrophilic front surface is oxygen terminated, and the front surface of the boron-doped diamond has a roughness of 1-20 (preferably 1-2) nm. The metal nanoparticles are deposited on a front surface of the boron-doped diamond, where the metal comprises a metal selected from: platinum, palladium, and/or gold (preferably platinum), where the boron-doped diamond is a single crystal diamond, and the metal nanoparticles are of height of 0.5-1.5 nm are randomly distributed across the front surface of the boron-doped diamond. The particle surface density of the metal nanoparticle-modified boron-doped diamond is 100-400 metal nanoparticles per mu m-2, where diffusional overlap is observed between neighboring particles. The boron doping concentration of the single crystal is of 70-100% homogeneous. The metal nanoparticle-modified boron-doped diamond comprises boron in a concentration of 1x 1020 to 1x 1019 boron atoms cm3, where the front surface of the single crystal is selected from (100), (110), (111), or (113) faces, or with a face that is preferably within plus minus 5 degrees of one of these faces. The metal or platinum nanoparticle-modified boron-doped diamond is coated with an at least partially gas permeable film, where the gas permeable film comprises a tetrafluoroethylene-perfluoro-3,6-dioxa-4-methyl-7-octenesulfonic acid copolymer. Preferred Method: The method (M1) involves rinsing the front surface of the boron-doped diamond with water, where deposition is electrochemical or chronoamperometric, and where the chronoamperometric deposition occurs at a potential of -0.8 to -1.0 V relative to a saturated calomel electrode. The deposition occurs over in the range of 0.1-10 (preferably 5-10) seconds. The deposition is effected using a multi-potential step technique. The boron-doped diamond column is prepared using laser cutting and a surface of this column comprises the acid-treated surface. In method (M2), only the front surface of the column is exposed, and the additional step of polishing at least part of the front surface of the column, where the polishing occurs prior to acid treating the front surface of the column. The metal nanoparticle-modified boron-doped diamond forms part of an electrode. EXAMPLE - No suitable example given.