PURPOSE: To obtain an oxygen concn. meter having a long service life by using a positive pole made of a metal (oxide) capable of reducing oxygen highly actively, a negative pole made of lead and an electrolyte containing a specified organic acid, a lead compound and furthermore alkali metallic salt, etc. of specified organic acid.
CONSTITUTION: The positive pole 1 is the metal such as Pt plate or the metallic oxide capable of reducing oxygen highly actively the negative pole 2 is lead and a copolymer diaphragm 4 consisting of F2O=CF2 and H2C=CH2 which is O2 transmissible is fixed by an O-ring to a holder 6 made of PVC in a galvanic cell type oxygen concn. meter. The mixed liquid having about 6.2pH and of a mixture of ≥2 kinds selected from group of acetic acid and propionic acid and N-butyric acid, alkali metallic salt or NH4 salt of aqueous organic acid such as formic acid, acetic acid, propionic acid, and PbO or lead salt of said organic acid is used as the electrolyte 6. Thereby, the oxygen concn. meter having no H2 gas generation and safety, no influence of CO2, enlarged solubility of Pb salt and remarkably longer service life than conventional meter is obtained.
TANIGAWA IKUO
FUJITA YUUKOU
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