Preliminary investigation of the application of on-line membrane extraction of trifluoroacetic acid as an aid to improvement of negative ion electrospray mass spectrometry data

We have recently investigated the biodegradation of a number of acidic arom atic compounds that give excellent chromatography using trifluoroacetic aci d (TFA) based HPLC methods. Unfortunately HPLC methods using TFA are not us ually compatible with detection by negative ion mass spectrometry as TFA su ppresses ionisation of the analyte during the electrospray process. We pres ent a preliminary investigation of the use of an anion-exchange micro-membr ane suppressor to remove TFA on-line post column with the aim of improvemen t of mass spectral data using an aromatic acid as an example. Thus LC-MS us ing a TFA based HPLC method with negative ion mass spectral detection is sh own to be possible with good sensitivity. (C) 2001 Elsevier Science B.V. hl l rights reserved.