I am looking for pH probes that can be inserted into a process line that can hit temperatures of 145 celcius. The pressure in the line is 50-100kPa. I know these types of sensors are out there but I cannot find a vendor.
Emerson and Honeywell manufacture pH sensors with high temperature/pressure ratings. Other vendors are also available.
You may check Emerson PERpH-X series models 3300HT/3400HT. It meets your pressure/temp specification. Honeywell HB Series electrodes may also meet your requirement.
Reduced life of probe and certain inaccuracies are problems of using regular pH probes in high temperature applications.
I think you are really pushing the limit. I have used probes above 100C but not that high. Perhaps a Field Effect or Antimony ring type. I will check some of my sources in the morning.
you seem to know what you're talking about. I'm doing a group project to design a probe suitable for measuring the pH on Venus. do you know of any pH sensors that work at around 450C?