I'm doing carboxyl-amine coupling with EDC-NHS on glass slides. With carboxylated glass in 2 different tubes, I put only EDC in one and EDC-NHS in the other tube. After some time I notice that bubbles are generated on my sample in the EDC-NHS tube. No bubbles were observed in the EDC-only tube.
Which gas is produced in this reaction that would form bubbles like that?
Thank you!