MSACL 2023 Abstract

Application of Magnetic Beads in Automated Sample Preparation for Simultaneous Measurement of Catecholamines and Metanephrines in Plasma by LC-MS/MS

Pengyun Liu(1), Yikun Li(2), Huafen Liu(3), William Wu(4)
Calibra Diagnostics

William Wu, PhD (Presenter) Calibra Diagnostics

Presenter Bio: Dr. Wu has a PhD in Clinical Chemistry and is board certified by American Board of Clinical Chemistry (ABCC). He also received his MBA from New York University Stern School of Business. He has more than 20 years experiences in clinical mass spec applications and previously held several management positions with increasing responsibilities in Quest Diagnostics. He was the best practice team Chair for LC-MS/MS for esteric business unit in Quest. He served as local section Chair for American Association for Clinical Chemistry (AACC) and currrently serve on the executive board of the Mass Spec and Separation Science Division at AACC. He is the Chief Scientific Officer for Calibra Diagnostics, a leading provider of diagnostics solutions using mass spectrometry in China.

Relevant Financial Disclosures (within past 24 months, reported on Jan 27, 2024) Stock/Bonds Calibra Diagnostics Conflict mitigation NOT REQUIRED.

Introduction:
The accurate quantitation of catecholamines and metanephrines in plasma is essential to clinically screen pheochromocytoma and paraganglioma. Automated and high throughput LC-MS/MS method for catecholamine and metanephrine measurement is desired to achieve quicker turn-around time, lower labor cost, and consistent testing results.

Methods:
Extraction of catecholamines and metanephrines from plasma samples was accomplished by using weak cation exchange (WCX) iron oxide magnetic beads. A magnetic bead extractor for 96-well plate was utilized for automated sample preparation. Sample analysis was performed by reverse phase HPLC with a PFP column and triple quadrupole mass spectrometer in the positive electrospray mode.

Results:
The method performance was fully evaluated with CLSI guideline C62-A. The accuracy of method was conducted by patient comparison as well as spiking recovery study. The overall bias of six analytes was less than 10%. The imprecision of six analytes was also less than 10%. The linearity of the method spanned 3 orders of magnitude. The lower limit of quantitation was 10 pg/mL for metanephrine as well as 3-Methoxytyromine, 15 pg/mL for dopamine, 20 pg/mL for normetanephrine as well as epinephrine, and 50 pg/mL for norepinephrine, respectively. The automated sample preparation time was 16 minutes for a 96-sample batch and LC-MS/MS analysis time was 4 minutes. This method was used for more than 5000 clinical sample analysis over the past six month and the cancelation rate was less than 0.2%, which is better than previous sample preparation method by WCX solid phase extraction (SPE).

Conclusion:
We have successfully developed an automated sample preparation method that uses WCX magnetic beads for simultaneous measurement of catecholamines and metanephrines by LC-MS/MS. This new method has excellent throughput for large number of clinical sample testing to meet the turn-around-time requirement from ordering physicians. In addition, as this new preparation method was selective, reliable, and less interference prone to the plasma matrix compared to the conventional SPE method, minimal cancelation rate should be expected for clinically screening pheochromocytoma and paraganglioma.