Title

Partial Enzymatic Elimination and Quantification of Sarcosine from Alanine using Liquid Chromatography-Tandem Mass Spectrometry

Abstract

Since sarcosine and d,l-alanine co-elute on reversed-phase high-performance liquid chromatography (HPLC) columns and the tandem mass spectrometer cannot differentiate them due to equivalent parent and fragment ions, derivatization is often required for analysis of sarcosine in LC/MS systems. This study offers an alternative to derivatization by employing partial elimination of sarcosine by enzymatic oxidation. The decrease in apparent concentration from the traditionally merged sarcosine-alanine peak associated with the enzymatic elimination has been shown to be proportional to the total sarcosine present (R2 = 0.9999), allowing for determinations of urinary sarcosine. Sarcosine oxidase was shown to eliminate only sarcosine in the presence of d,l-alanine, and was consequently used as the selective enzyme. This newly developed technique has a method detection limit of 1 µg/L (parts per billion) with a linear range of 3 ppb-1 mg/L (parts per million) in urine matrices. The method was further validated through spiked recoveries of real urine samples, as well as the analysis of 35 real urine samples. The average recoveries for low, middle, and high sarcosine concentration spikes were 111.7, 90.8, and 90.1 %, respectively. In conclusion, this simple enzymatic approach coupled with HPLC/MS/MS is able to resolve sarcosine from d,l-alanine leading to underivatized quantification of sarcosine.

Department(s)

Chemistry

Keywords and Phrases

Alanine; Amino Acids; Chemistry; Chromatography; Enzymatic Elimination; Evaluation; High Performance Liquid Chromatography; High Pressure Liquid; HPLC/MS/MS; Human; Male; Mass Spectrometry; Methodology; Oxidation Reduction Reaction; Prostate Tumor; Prostatic Neoplasms; Reversed Phase Liquid Chromatography; Reverse-phase; Sarcosine; Sarcosine Oxidase; Tandem Mass Spectrometry; Tissue; Urine

International Standard Serial Number (ISSN)

16182642

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2013 Springer Verlag, All rights reserved.


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