Analysis of the acidic microenvironment in murine tumours by high-performance ion chromatography.

High-performance ion chromatography (HPIC) has been utilised to probe the biochemistry associated with changes in tumour pH following total vascular occlusion. Samples from the tumour extracellular compartment were obtained by insertion of a microdialysis probe and analysed by HPIC with conductivity detection. Separations were carried out by ion-exclusion chromatography using an IonPac ICE AS1 weak-acid column. The eluent (0.5 mM octanesulphonic acid) was chemically suppressed with 5 mM tetrabutylammonium hydroxide through a micromembrane suppressor. After complete vascular occlusion induced by a clamp, lactate levels increased in the extracellular compartment.