Storing a pH sensor dry is not good, but our sensors are pretty tough and the pH probes can survive being stored dry for a short period of time. Please do this to test a pH probe:
1. Plug it into an interface and start the data collection software.
2. Pour ~50 mL of pH 4 buffer into a small beaker. If you don't have pH 4 buffer, use regular grocery store vinegar (pH = ~2.5). Remove the storage bottle and cap from the pH sensor and place the sensor in the beaker of liquid so it is immersed an inch or two in the liquid.
3. Check the pH reading. If it is anywhere close to the known pH of the liquid, any reading below 7, then you can probably revive it. If the reading is higher than 7, then the probe is probably so weak that it can't be revived. If the reading is ~13.6, then the probe is dead and needs to be replaced.
To revive a probe that has been stored dry, but doesn't appear to be dead, see:
TIL 730: The pH electrode I have been using no longer seems to work or is slow to respond. Is there anything I can do to fix it?