Process and arrangement for measuring ion strength

US4511660A · kind A · utility

Inventors

• Dietrich W. Lubbers · Dortmund, DE
• Norbert Opitz

Key dates

• Filing date: Jun 10, 1983
• Grant date: Apr 16, 1985
• Expiry date: Jun 10, 2003

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N33/84
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Process and apparatus for directly measuring the ion strength of an electrolyte solution is disclosed. The pH value of the electrolyte is measured by means of a first measurement with a first indicator dependent on the ion strength and by means of a second measurement with a second indicator dependent on ion strength in a manner different from the first indicator whereby the ion strength is computed by means of the approximation ##EQU1## J=ion strength Jo=ion strength upon calibration PA0 pH'(N)=pH value, measured with a first indicator N dependent on the ion strength (HPTS) PA0 pH'(X)=pH value, measured with a second indicator X dependent on the ion strength, the ion strength dependence of which is different from that of the first indicator PA0 W(N)=valency of the first indicator PA0 W(X)=valency of the second indicator with ##EQU2## The ion strengths of other ions and of unknown electrolyte may also be computed.