Does the Sampling Rate affect the syncing process to a video source? I have recorded interviews using a point and shoot camera for the video and my android phone with Smart Recorder. The camera records in MOV and is uncompress with mono audio. Then I use my smartphone to record myself and the interviewee, since the camera is far away to hear us. The audio is in .wav and I use Premiere Pro to align them. While it does work at the start, sometimes it magically gets out of sync all of the sudden, so I have to cut the audio so that I can catch up. 

I am puzzled, and would like to have your insights on how to keep this at a minimum if possible, eliminate it. My theory is that sampling rate is an issue. If this is incorrect, please advice otherwise.
You can tell which one gets out of synch like this:

Set up your camera and your phone like you usually do. Put a clock that shows seconds right in front of the camera. Then, even though this sounds boring, record yourself counting off the seconds.

Synchronize the video and audio in Premiere Pro like you usually do. When they get out of synch, check whether the video lost a second, or whether the audio lost a second. You should be able to tell based on the repetitive rhythm.

Then, as @AJHenderson pointed out, you should replace the piece of equipment that failed. I agree that a camera that can accept external audio input is probably the best option, though it's expensive.