I've worked in a lot of labs and I've never seen a mass spec that can process a bag. However, funny you should mention spitting for a test...just today a med student from U of I told me they've developed a spit test they are going to be using for staff/students as they return to Campus this fall. Not sure if they have any plans to make it widely available, but there sensitivity and specificity is on par with the test of the options we currently have. My assumption is they'll be spitting in a sterile specimen cup, though.

They have a test now. It entails inserting a swab in each nostril. What's the big deal? Let's test and trace. Insulate cases and quarantine. We may be at the point of no return but we can try. Some imaginary breathe in a bag test? What difference does it make?