Is it possible that with an inert GCMS I do analyze SO2, N2O and NO2 in medical grade oxygen ? Is PDHID a better detector for this analysis with impurities concentrations at lower than 1 PPM total ?

It is difficult to quantitate NO2 by GC because of the instability of NO, NO2. Please refer to the below article.

Can I analyze NO, N2O and NO2 via GC? (restek.com)

We can analyze the low level (below 1ppm) SO2 and N2O by GC-PDHID or GC-MS with PLOT column. (PLOT Q or U?, it have to be considered.)

As alternaete method, the selective detector (ECD and SCD) is also useful and detect the lower than 1ppm.

Thank you very much.