Simplified Methylmalonic Acid Analysis without Derivatization in Human Plasma by LC-MS/MS

Published By: Restek Corporation

Year of Publication: 2018

Link: http://www.restek.com/Technical-Resources/Technical-Library/Clinical-Forensic-Toxicology/cft_CFSS2829A-UNV

Abstract: 

Methylmalonic acid analysis is an important clinical test for diagnosing vitamin B12 deficiency as well as methylmalonic acidemia. Methods typically require extensive sample preparation, which involves significant time and expense. The LC-MS/MS method developed here offers a much simpler alternative, providing complete chromatographic resolution of isobaric analytes from the direct injection of a protein crash sample supernatant onto a Force C18 column.

LC-MS/MS Analysis of Urinary Free Cortisol and Cortisone without Matrix Interferences

Published By: Restek Corporation

Year of Publication: 2018

Link: http://www.restek.com/Technical-Resources/Technical-Library/Clinical-Forensic-Toxicology/cft_CFSS2824-UNV

Abstract: 

In general, LC-MS/MS analysis of urinary free cortisol and cortisone can provide better specificity than immunoassay-based methods. However, it is critical that the analytical column has the proper selectivity for chromatographically separating cortisol from isobaric matrix components. In the method presented here, complete separation of the target analytes and matrix interferences was obtained in a 3-minute analysis on a Raptor Biphenyl column.

Simultaneous Analysis of Catecholamines and Metanephrines in Urine by LC-MS/MS

Author: Shun-Hsin Liang and Frances Carroll

Published By: Restek Corporation

Year of Publication: 2017

Link: http://www.restek.com/Technical-Resources/Technical-Library/Clinical-Forensic-Toxicology/cft_CFAN2800-UNV

Abstract: 

Clinical diagnosis of pheochromocytoma and paraganglioma is often based on the analysis of catecholamines (epinephrine, norepinephrine, dopamine) and metanephrines (metanephrine, normetanephrine, 3-methoxytyramine) in urine. Analysis of these polar compounds using reversed-phase LC can be difficult due to limited chromatographic retention, which results in poor separation of the analytes from closely eluting matrix interferences. This method overcomes these problems by combining a simple solid phase extraction procedure with the consistent and accurate chromatographic performance of a Raptor Biphenyl column.