Bismuth-Film Electrodes (BFEs)

Bismuth-film electrodes are a class of electrochemical sensor in which a thin bismuth film is deposited on a substrate and used in place of a mercury film electrode for stripping voltammetry. They appear in the appended bibliography of the Craig dossier as an example of how bismuth films became a legitimate analytical-chemistry subject decades after the 1920s dispute. The source does not connect this literature to Craig's device.

Why bismuth replaces mercury

The Hutton, Hocevar and Ogorevc paper in the source describes the ex situ bismuth film microelectrode as a "promising non-toxic, environmentally friendly microsensor" and notes a "distinct practical advantage" over mercury film microelectrodes. The bibliography covers substrate materials, film formation and cleaning, detection techniques, interferences, and target analytes.

Reported performance

• Ex situ bismuth film microelectrodes (BiFMEs). Hutton, Hocevar and Ogorevc (Analytica Chimica Acta 537(1–2):285–292, 2005) pre-plated bismuth potentiostatically onto a single carbon fibre, optimised for long-term electrochemical and mechanical stability. AdCSV of Co(II) and Ni(II) gave detection limits of 70 and 90 ng/l with RSD of 2.4% and 2.9% at 1 µg/l (n = 10) using 2 min preconcentration in the presence of dissolved oxygen. The electrodes were also demonstrated for ASV of Cd(II) and Pb(II), and are described as showing a "distinct practical advantage" over mercury film microelectrodes.
• Screen-printed carbon electrodes. Serrano, Díaz-Cruz, Ariño and Esteban (Electroanalysis 22(13):1460–1467, 2010) report ex situ deposited bismuth film on screen-printed carbon electrodes as a disposable device for stripping voltammetry of heavy metal ions.
• Directly heated electrodes on gold microwires. Jacobsen, Duwensee, Wachholz, Adamovski and Flechsig report directly heated bismuth film electrodes on gold microwires, with a wider potential window than bare gold, higher signals for picric acid, temperature pulse amperometry (TPA) enhancement, and preliminary detection of 3 ppm picric acid.

See also

Thin Bismuth Film Preparation, Sono-Electroplating of Bismuth Films and the Low-Field Hall-Effect Dispute.