Abstract: It is an object of the present invention to provide an electrochemical sensor which can prevent occurrence of cracks at the welding portion between a support tube made of lead-free glass and a sensitive glass membrane or ceramics, and a method for manufacturing the same. The electrochemical sensor 100 has a configuration such that the sensitive glass membrane 2A is welded to the support tube 1 made of lead-free glass with a lead glass layer 3A between the sensitive glass membrane 2A and the support tube 1. According to the present invention, there is also provided the electrochemical sensor in which the ceramics 2B for a junction is welded to the support tube 1 made of lead-free glass with a lead glass layer 3B between the ceramics 2B and the support tube 1.

Abstract: This invention relates to a pH measuring electrode having a sensor film which is sensitive to a hydrogen ion (H.sup.+) in the solution. The pH measuring electrode of this invention has a sensor film of a metal oxide deposited on an electrically insulative ceramics substrate so that the sensor film can be very miniaturized in its size. Therefore, the entire pH measuring electrode can be made considerably small and simple in construction. Also, this invention provides another pH measuring electrode which further includes a porous film of an insulation material coated on the surface of the metal oxide sensor film so that the sensor film is not affected by any coexistent substances.

Abstract: This invention relates to a pH measuring electrode having a sensor film which is sensitive to a hydrogen ion (H.sup.+) in the solution. The pH measuring electrode of this invention has a sensor film of a metal oxide deposited on an electrically insulative ceramics substrate so that the sensor film can be very miniaturized in its size. Therefore, the entire pH measuring electrode can be made considerably small and simple in construction. Also, this invention provides another pH measuring electrode which further includes a porous film of an insulation material coated on the surface of the metal oxide sensor film so that the sensor film is not affected by any coexistent substances.

Abstract: This invention relates to a pH measuring electrode having a sensor film which is sensitive to a hydrogen ion (H+) in the solution and method of manufacturing the same. The pH measuring electrode of this invention has a sensor film of a metal oxide deposited on an electrically conductive support so that the sensor film can be very miniaturized in its size. Therefore, the entire pH measuring electrode can be made considerably small and simple in construction. Also, this invention provides another pH measuring electrode which further includes a porous film of an insulation material coated on the surface of the metal oxide sensor film so that the sensor film is not affected by any coexistent substances.