Chromatography Forum

I have developed a method for Citrate in Human Plasma using Ion Chromatography (ICS-3000 RFIC, KOH mobile Phase, AS-11 column, 23mM -30mM gradient over 6 mins, then a cleanup ramp and re-equilibriate over two minutes).

I started using 100uL plasma + 30uL 20% TCA to crash the proteins, followed by dilution of 30uL to 1mL and injection of 50uL, but TCA produced a peak that co-eluted with citrate. As a result I switched to 20% TFA which seems to work, however I've noticed a trend of reducing retention times, even after just 200 injections.

So, can my AS-11 column cope with a smidge of TFA ? Or is something else the problem ? Does anyone else have any strategies for Plasma sample prep and IC ?

Thanks

Paul.

The Use of TFA is very uncommer in ion chromatography, b'use TFA itself gives u the triflet ion and this ion on higher concentration deposited on the stationary column. so if u are working on TFA please regenerate the column even after every 20 injection so your column gives u the best performance.