Department of Clinical Pathology, Cleveland Clinic, Cleveland, OH, USA.
Clin Chem Lab Med. 2011 Jul;49(7):1213-6. doi: 10.1515/CCLM.2011.195. Epub 2011 May 17.
Measuring urinary fractionated metanephrines is one of the initial tests in the diagnosis of pheochromocytoma. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) represents the most specific and accurate technology for this purpose. The goal of this work was to develop a simple LC-MS/MS method for measuring metanephrines in urine.
Each urine sample was complexed with diphenylboronic acid, and purified on a Bond-Elute Plexa cartridge. The extract was concentrated and analyzed on a short Atlantis T3 column in 8.5 min. Metanephrines and their deuterated internal standards were monitored in positive electrospray ionization mode by multiple reaction monitoring.
Ion suppression was observed, but was compensated for by the respective internal standard. The analytical measurement range was 0.2-27.4 μmol/L and 0.3-14.6 μmol/L for metanephrine and normetanephrine, respectively. The intra-assay and total coefficient of variation throughout the linear ranges was 2.03%-2.11% and 2.20%-3.80% for metanephrine, and 4.50%-8.09% and 9.00%-10.00% for normetanephrine, respectively. Comparison with a commercial HPLC method using patient samples (n=65) by Passing-Bablok regression showed a slope of 1.000 and 1.014, y-intercept of -0.080 and -0.067, a correlation coefficient of 0.8830 and 0.9022, and a mean difference of 14.0% and -0.43% for metanephrine and normetanephrine, respectively.
This simple method for urine metanephrines is suitable for clinical use.
检测尿中游离的甲氧基肾上腺素是诊断嗜铬细胞瘤的初始检测之一。液相色谱-串联质谱法（LC-MS/MS）是目前最特异和准确的检测方法。本研究旨在建立一种简单的 LC-MS/MS 方法来检测尿液中甲氧基肾上腺素。
尿液样本与二苯硼酸络合，经 Bond-Elute Plexa 小柱纯化。提取液经浓缩后，在 Atlantis T3 短柱上 8.5 分钟内进行分析。采用正电喷雾离子源和多反应监测监测甲氧基肾上腺素及其氘代内标。
观察到离子抑制，但通过各自的内标得到了补偿。甲氧基肾上腺素和去甲氧基肾上腺素的分析测量范围分别为 0.2-27.4 μmol/L 和 0.3-14.6 μmol/L。在整个线性范围内，甲氧基肾上腺素和去甲氧基肾上腺素的批内和总变异系数分别为 2.03%-2.11%和 2.20%-3.80%，4.50%-8.09%和 9.00%-10.00%。与采用患者样本的商业 HPLC 方法（n=65）比较，通过 Passing-Bablok 回归分析显示，甲氧基肾上腺素和去甲氧基肾上腺素的斜率分别为 1.000 和 1.014，y 轴截距分别为-0.080 和-0.067，相关系数分别为 0.8830 和 0.9022，平均差值分别为 14.0%和-0.43%。
该方法简便，适用于临床检测尿液中甲氧基肾上腺素。
