Determination of creatine and guanidinoacetate by GC-MS

Evaluation of a GC-MS method using N- tert-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA) as the silylating agent for GC-MS. Study of the stability of creatine and guanidinoacetate in urine. 22 urines were kept at RT, 4 °C and − 30 °C for 15 days. MTBSTFA produces a single chromatographic p...

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Published inClinical biochemistry Vol. 42; no. 1; pp. 125 - 128
Main Authors Prieto, José Angel, Andrade, Fernando, Martín, Sergio, Sanjurjo, Pablo, Elorz, Javier, Aldámiz-Echevarría, Luís
Format Journal Article
LanguageEnglish
Published Elsevier Inc 2009
Subjects
Creatine
Gas chromatography-mass spectrometry
Guanidinoacetate
Stability
Urine
Urine
Stability
Gas chromatography-mass spectrometry
Creatine
Guanidinoacetate
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Summary:Evaluation of a GC-MS method using N- tert-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA) as the silylating agent for GC-MS. Study of the stability of creatine and guanidinoacetate in urine. 22 urines were kept at RT, 4 °C and − 30 °C for 15 days. MTBSTFA produces a single chromatographic peak in contrast with other derivatizing agents. Creatine concentration increases at room temperature (326% on average), and at 4 °C (75%). However, detection decreases after freezing (− 37%). Guanidinoacetate is stable, but decreases after freezing (− 37%). Sonication before analysis is crucial to obtain repetitive results. A modified GC-MS method has been validated and the conditions for preservation of the urine have been established.
ISSN:0009-9120
1873-2933
DOI:10.1016/j.clinbiochem.2008.10.001