Can GC be used to detect oxygen evolution? To quantify it? If not, why not?

You can identify (via co-chromatography with standard) and quantify oxygen on a GC equipped with a thermal conductivity detector.

Make sure, though you are able to separate oxygen from argon. These two components often elute at the same time on most columns. Restek developed a cppliary column similar to a packed mol sieve that does the job.