Metabonomic studies comparing capillary and conventional HPLC-oa-TOF MS for the analysis of urine from Zucker obese rats

The application of capillary HPLC and orthogonal acceleration (oa) TOF-MS to a metabonomic investigation of the urinary metabolic profiles of samples obtained from male and female Zucker rats is described. The results obtained using capillary HPLC for performing the chromatographic separation are also compared with the analysis of the same samples by conventional HPLC. Capillary HPLC-MS gave increased sensitivity (ca. 100 fold) despite using a fraction of the sample volume consumed by HPLC (0.5 mu L vs 10 mu L). Capillary HPLC-MS also provided a greater peak count (ca. 3000 ions compared to 1500 for HPLC) for the same analysis time compared to conventional HPLC-MS. These data were processed using partial least squares discriminant analysis (PLS-DA) enabling markers of diurnal variation to be detected for urine samples from both male and female rats.