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- Posts: 3
- Joined: Fri Mar 30, 2018 3:16 am
I'm working on an LCMS method for THCCOOH (carboxy-THC) in urine and I noticed that I get dramatically different signals depending on the pH of the buffer I add during sample prep. At pH7 signals are about 25 fold lower than they are with the pH5 buffer. Does anyone know what could be causing this?
My first thought was THC sticking to glass/plastic to a higher extent at pH7, or maybe some kind of improved ionisation effect at the source (ESI negative). Any ideas?
Thanks for your help
H