Chemical signal-impermeable mask

(57) A summary chemistry signal nontransparent nature mask (1) is arranged in an electrolyte style, as this mask is between the work electrodes (4) which detect the chemistry signal conveyed from the source of supply of a chemistry signal, and a source of supply (for example, diffusion). The composition of a mask prevents transportation of all the chemistry signals substantially from the chemistry signal source of supply to which this mask has a radial vector ingredient to a mask surface and the catalyst surface of a work electrode, Thereby, only a perpendicular chemistry signal is mainly substantially conveyed to a mask surface and the catalyst surface (6) of a work electrode. By reducing or removing transportation of the radial direction of the chemistry signal which faces to a work electrode, this mask reduces or removes the border effect remarkably. By reducing substantially the border effect produced by transportation of the radial direction of a chemistry signal, it becomes possible to measure more correctly the quantity (for example, concentration) of the chemistry signal conveyed from the arbitrary domains of the material of a source of supply.