GABA/glutamate detection with OPA derivatisation - help!
Posted: Wed Oct 24, 2007 2:15 pm
Hi
I'm hoping someone can point me in the right direction, I am currently trying to set up our system for detection of GABA and glutamate. I have followed methods for OPA derivatisation with GABA and glutamate standards, but when I inject these all I see is a peak for OPA.
I'm using:
Waters 1525 pump, 717plus Autosampler, 2465 EC detector
Atlantis T3 column 3um, 2.1 x 150mm
Based on information given to me, I've tried mobile phases with 10% and 25% methanol concentrations (at pH 5.6 and 4.4 respectively). (Both with 0.1M sodium phosphate and 0.05mM EDTA)
OPA is allowed to react with the standards for 10 minutes at room temperature before injection, standards are in 0.1N perchloric acid.
After 30 mins at flow rate of 0.2 or 0.15ml/min there are no peaks other than the first (very large) one for OPA.
My lack of experience/knowledge in this area means I'm not sure what to try next, so any help would be greatly appreciated!
Thanks, Carly
I'm hoping someone can point me in the right direction, I am currently trying to set up our system for detection of GABA and glutamate. I have followed methods for OPA derivatisation with GABA and glutamate standards, but when I inject these all I see is a peak for OPA.
I'm using:
Waters 1525 pump, 717plus Autosampler, 2465 EC detector
Atlantis T3 column 3um, 2.1 x 150mm
Based on information given to me, I've tried mobile phases with 10% and 25% methanol concentrations (at pH 5.6 and 4.4 respectively). (Both with 0.1M sodium phosphate and 0.05mM EDTA)
OPA is allowed to react with the standards for 10 minutes at room temperature before injection, standards are in 0.1N perchloric acid.
After 30 mins at flow rate of 0.2 or 0.15ml/min there are no peaks other than the first (very large) one for OPA.
My lack of experience/knowledge in this area means I'm not sure what to try next, so any help would be greatly appreciated!
Thanks, Carly