气相色谱-质谱联用仪测定肌酸和胍基乙酸：研究其在不同温度下于尿液中的稳定性
Determination of creatine and guanidinoacetate by GC-MS: study of their stability in urine at different temperatures.
作者信息
Prieto José Angel, Andrade Fernando, Martín Sergio, Sanjurjo Pablo, Elorz Javier, Aldámiz-Echevarría Luís
机构信息
Division of Metabolism, Cruces Hospital, 48903 Barakaldo, Spain.
出版信息
Clin Biochem. 2009 Jan;42(1-2):125-8. doi: 10.1016/j.clinbiochem.2008.10.001. Epub 2008 Oct 22.
OBJECTIVES
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.
DESIGN AND METHODS
22 urines were kept at RT, 4 degrees C and -30 degrees C for 15 days.
RESULTS
MTBSTFA produces a single chromatographic peak in contrast with other derivatizing agents. Creatine concentration increases at room temperature (326% on average), and at 4 degrees 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.
CONCLUSIONS
A modified GC-MS method has been validated and the conditions for preservation of the urine have been established.
目的
评估一种使用N-叔丁基二甲基硅烷基-N-甲基三氟乙酰胺（MTBSTFA）作为气相色谱-质谱联用（GC-MS）硅烷化试剂的方法。研究尿液中肌酸和胍基乙酸的稳定性。
设计与方法
将22份尿液分别在室温、4℃和-30℃下保存15天。
结果
与其他衍生化试剂相比，MTBSTFA产生单一色谱峰。肌酸浓度在室温下平均增加326%，在4℃下增加75%。然而，冷冻后检测值下降（-37%）。胍基乙酸稳定，但冷冻后下降（-37%）。分析前超声处理对于获得重复性结果至关重要。
结论
一种改良的GC-MS方法已得到验证，并确定了尿液保存条件。
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