Highly sensitive analysis of metanephrines in plasma is critical in the diagnosis and treatment of pheochromocytoma and paraganglioma. Here, a HILIC LC-MS\/MS method was developed using a Raptor HILIC-Si column because this approach provides retention of all target compounds in highly organic mobile phases, thus providing the increased sensitivity needed to reach low detection limits. Data from linearity, accuracy, and precision testing demonstrate that accurate results are consistently obtained\u2014even at trace levels\u2014for these important clinical biomarkers.<\/p>\n\n\n\n
The metanephrines\u2014metanephrine (MN), normetanephrine (NMN), and 3-methoxytyramine (3-MT)\u2014are methylated metabolites of epinephrine, norepinephrine, and dopamine, respectively (Figure 1). These catecholamine metabolites are released from the adrenal medulla and sympathetic nervous cells and are normally maintained at very low concentrations in the bloodstream. Elevated levels of these compounds in circulation can indicate the presence of pheochromocytoma or paraganglioma, so highly sensitive measurement of in vivo<\/em> concentrations is critical for correct diagnosis, treatment, and long-term patient monitoring.<\/p>\n\n\n\n Trace-level analysis of metanephrines in plasma using typical reversed-phase LC can be difficult due to limited chromatographic retention and lack of sensitivity. As an alternative, we developed an LC-MS\/MS method based on hydrophilic interaction liquid chromatography (HILIC) using a Raptor HILIC-Si column. Combined with a simple solid phase extraction (SPE) procedure, an accurate and precise analysis of these important biomarkers can be achieved in a fast, 5-minute analysis time, making this a beneficial assay for high-throughput clinical labs.<\/p>\n\n\n