Which process media can damage pH sensors?

Some process media can shorten pH sensor lifetime or affect measurement accuracy. Understanding these challenges helps you select the right sensor design and implement appropriate maintenance practices.

• Hydrofluoric acid (HF): Attacks and dissolves the glass membrane. HF glass can be used to reduce this effect.
• Strong caustics (NaOH, KOH): Accelerate glass aging and can cause alkali error. H glass offers the lowest alkali error.
• Hot caustics (NaOH): Place additional stress on the glass membrane. PHI glass is the most robust pH glass for this application.
• Sulfide-containing media: Can poison the reference system.
• Organic solvents and low-water media: Dehydrate the glass membrane, reducing performance.  
• Slurries, proteins, and polymers: Foul the membrane and clog the reference junction.  
• Abrasive suspensions: Mechanically wear the glass and junction.