Carbon-fiber microsensor for in vivo monitoring of trace zinc(II) based onelectrochemical stripping analysis

optimization and characterization of a microsensor for trace zinc based on stripping voltammetry at a single carbon-fiber microelectrode are reported. Despite the absence of a mercury coverage, the carbon-fiber stripping sens or displays a significant hydrogen overvoltage in the physiological pH and a well-defined zinc stripping peak (at ca. -1.17 V). 5 s deposition periods allow convenient quantitation of zinc over the 100-1000 ng/ml (ppb) range. Detection limits of 0.8 ng/ml (1.2 x 10(-8) M) and 20 ng/ml (3.0 x 10(-7) M) zinc were estimated in connection to 60 and 1 s deposition, respectively . The response is reversible with the stripping/measurement step completely removing the accumulated zinc. Measurement frequencies as high as 30 runs per min can thus be realized (in connection to 1 s deposition and measureme nt steps). The influence of relevant variables of the deposition and stripp ing steps is examined. The attractive behavior of the stripping-voltammetri c microsensor offers great promise for in vivo monitoring of trace levels o f zinc. (C) 2001 Elsevier Science B.V. All rights reserved.