I don't think there's a way around periodic calibration if you want precise measurements. At least not with normal glass electrodes. If the precision requiremen

I don't think there's a way around periodic calibration if you want precise measurements. At least not with normal glass electrodes. If the precision requirements are loose, you could go months between calibration. If you're trying to get within 0.1pH, every few weeks or so. For anything that's going in a scientific paper, calibration before every use is important. There might be a clever way around this, like with a tech other than glass electrode, or some type of automation system with motors that raise and lower the probe into calibration solutions. Something interesting: pH electrode response is nearly linear, and you can make the transfer function using entirely 2 (or 3 to compensate for non-linearity) calibration points. (voltage, pH, temp) No arbitrary coefficient required, other than maybe temp compensation. Edit: I wonder if your sampling idea could kill 2 birds with one stone, if implemented well: By sampling using a mechanical system, you could measure regularly, and calibrate. Auto calibration, and avoid the lifetime reduction from immersion. Eg some type of motor/pump system connected to the electrode.