I think I talked too early and I feel I was wrong and would like to take back my previous comment. I have never used TEA and found some people saying it's okay (like in the link of my previous comment or this: http://www.colby.edu/chemistry/instruments/ElectrosprayIntro.pdf), but no one actually using it. I'm sure Tom is right, and it causes ion suppression, specially in the negative mode, you'd also see the TEA alone (depending on you acquisition window) and adducts of M+TEA in the positive mode. honestly, I've only used ammonium hydroxide and formic acid for my buffers. On the other hand, sometimes you have to compromise for whatever reason and if you can deal with the problems afterwards, it's your choice.
Sorry about the change of mind but, that's how this works, right?