Silver@-silver halide reference electrode prepn. for long life - by in-situ pptn. of silver halide, for amperometric and potentiometric two and three electrode probes with gel type or polymer electrolyte, monomer and/or prepolymer, etc.

摘要

The prepn. comprises surrounding a silver wire by a defined amt. of dense solid silver halide (II) in electrolyte contact with a soln. of constant halide ion concn. (III) as an inner reference soln.. The solid (II) is permanently in a liq. the housing to at least a predetermined level and the liq. is placed in the housing before the silver halide. Also new is the use of element (I) as a half cell in the construction of: (i) a pH or redox electrode comprising potentiometric combination electrodes, (ii) an amperometric electrode comprising a two electrode measuring probe, and (iii) a three electrode measuring probe contg. a measuring electrode and an auxiliary electrode. Pref. (II) is prepd. by in-situ pptn. in the liq. the housing by mixing of two solns. (of silver nitrate and potassium halide). (II) is pref. silver chloride. One of the two solns. is used as the inner reference electrolyte. The housing is filled by a funnel to produce an excess of liq. and (II) is deposited at the bottom of the housing. The housing is shaken during or after filling. The inner reference soln. is a potassium halide, (potassium chloride soln.) of 3, 3.5 molar or is satd. A gel type or polymer electrolyte is used and the potassum halide soln. is mixed with monomers and/or prepolymers and opt. polymerisation and/or crosslinking catalysts to form a polymer in the housing or in the funnel. The halide ion is bromide or iodide and a large excess of halide ion soln. is maintained in contact with the inside of the housing. The housing is immersed into the halide ion soln. so the filling point is held beneath the surface of the soln.. The silver wire is inserted into the pptd. (II) and halide ion soln. the housing which is pref. a narrow tube or the wire is glued to the base of the housing prior to filling . The silver wire is lengthened with platinum that is fused into the base of the housing. USE/ADVANTAGE - The prepn. is simple and produces a (I) with a controlled and reproducible amt. of (II). (I) have a long life and are useful in amperometric and potentiometric two and three electrode probes.