46. Extraction of Plasma Free Metanephrine (MN) and Normetanephrine (NMN) Using Strata™-X-CW and LC/MS/MS on Luna® HILIC
Poster: Tue 6:30-7:30PM
Philip J. Koerner
Carl Sanchez, Shahana Wahab Huq, Philip J. Koerner

Phenomenex, Inc., 411 Madrid Avenue, Torrance, CA 90501, USA
The measurement of plasma free metanephrine (MN) and normetanephrine (NMN) has been reported in the literature to be the best tool in the diagnosis and identification of pheochromocytoma patients. In this poster we present a method for the extraction and concentration of free metanephrines from plasma using a polymeric weak cation exchange resin (Strata™-X-CW) followed by LC/MS/MS analysis using a Luna® 3 μm HILIC HPLC column. Under HILIC conditions the very polar MN and NMN are easily retained and well resolved in less than 5 minutes. The method LLOQ was determined to be 0.5 ng/mL with good linearity (R2 = 0.9993 and 0.9991 for MN and NMN, respectively) over the entire concentration range (0.5 to 200 ng/mL). Precision and accuracy were determined by spiking the plasma matrix at four concentrations (0.5, 1.5, 100, and 180 ng/mL) in replicate (n=6) and found to be within the acceptable range for bio-analytical validation.