The use of ultra performance liquid chromatography (UPLC™) has gained much interest since it offers several advantages, namely improved chromatographic resolution, increased sensitivity and reduced analysis times. This is achieved through the use of small particle sizes (< 2um) and pumping / injection systems capable of operating under such exacting pressure regimes (up to 15,000 psi). When coupled with time of flight mass spectrometry, UPLC presents a means to achieve high sample throughput with, reduced spectral overlap, increased sensitivity and exact mass detection capabilities. This aspect of UPLC- MS(TOF) is particularly attractive for metabolite ID and metabonomics applications where the rapid and accurate detection and identification of potential drug metabolites, impurities and biomarkers by exact mass is beneficial.

We have recently applied UPLC-MS(TOF) to the metabonomics analysis and elucidation of urinary endogenous biomarkers of gender, genetic state and temporal variations in (+/+, +/- and -/-) Zucker rats. The results presented here will demonstrate the positive impact that high-pressure separations have on resolution and sensitivity. Furthermore, use of UPLC results in the detection of more peaks, which implies that an increased number of possible metabolites and biomarkers may be found. Several biomarkers of have been detected using this approach, and will be discussed in terms of biological relevance.