Quantitative Small Molecule Bioanalysis Using Chip-Based NanoESI-MS/MS

A fully automated chip-based nanoelectrospray (nanoESI) system, NanoMate® 100 (Advion Bio-Sciences, Inc., Ithaca, NY), was evaluated for its application on quantitative bioanalysis of small molecules in support of exploratory pharmacokinetic (PK) studies. The NanoMate® 100 was compared with the conventional autosampler coupled with liquid chromatography-electrospray (LC-ESI) interface. An API® 3000 triple quadrupole mass spectrometer (Applied Biosystems, Inc., Foster City, CA) was used for the evaluation. The results show that the NanoMate® 100 performs comparably to LC-ESI in terms of standard curve fitting, low limit of quantitation (LLOQ), dynamic range, accuracy, and precision. Parallel analyses of exploratory PK study samples show high correlation ( R 2 = 0.971) between the NanoMate® 100 and the LC-ESI. The NanoMate® 100 exhibits advantages in carryover, sample consumption, sample cycle time, and the ability to be full automated. Despite these advantages, the necessarily rigorous sample preparation process limits the application of the NanoMate® 100 for quantitative analysis in areas such as exploratory PK studies, which often involve multiple compounds in one study and require rapid turnaround. However, the NanoMate® 100 has great potential in qualitative work (e.g., metabolite identification) as well as in high-throughput quantitative analysis of compound in the development stage (i.e., a single analyte with a well-established sample extraction method). (JALA 2004;9:109-16)