摘要 |
An inexpensive, high-performance pH sensor measure the surface of a solid substance in a simple manner, comprising an ion sensing part 2 which responds to pH, a reference electrode 3, a gel-form ion permeable substance 10, which has a predetermined pH value and covers the ion sensing part 2 and reference electrode 3, and a cover member 9, which houses the ion permeable substance 10 and has an opening 9a formed at a position near the abovementioned ion sensing part 2.
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