Gamache P H, Kingery M L, Acworth I N
ESA, Inc., Bedford, MA 01730.
Clin Chem. 1993 Sep;39(9):1825-30.
We describe a procedure for the direct measurement of metanephrine (MN) and normetanephrine (NMN) in hydrolyzed urine, using HPLC with coulometric array detection. Acid-hydrolyzed samples were diluted and filtered before separation by isocratic reversed-phase ion-pair chromatography. Eight serial coulometric sensors, set at incrementally increasing anodic potentials, were used to screen lower-oxidizing interferences and provide stepwise oxidation of the metanephrines. Voltammetric behavior across three adjacent sensors was used to assess resolution and aid in peak identification. Values obtained in commercial controls were consistently within the specified target range. Variability, expressed as CV, was 5.45-9.22% between runs and 1.60-4.52% within-run for both compounds. The limit of detection was 2.6 micrograms/L for MN and 2.8 micrograms/L for NMN, with a linear response to 15.0 mg/L for both analytes. Results from patients' samples correlated well with those by a method involving dual ion-exchange extraction (r = 0.963, n = 82 for MN; r = 0.9768, n = 83 for NMN). This procedure provided high selectivity and objective peak purity information while greatly simplifying sample preparation.
我们描述了一种使用带电量分析阵列检测的高效液相色谱法直接测量水解尿液中变肾上腺素（MN）和去甲变肾上腺素（NMN）的方法。酸水解样品在通过等度反相离子对色谱法分离前进行稀释和过滤。使用八个串联的电量传感器，设置为逐步增加阳极电位，以筛选低氧化性干扰物并提供变肾上腺素的逐步氧化。利用三个相邻传感器的伏安行为来评估分离度并辅助峰识别。在商业对照中获得的值始终在指定的目标范围内。两种化合物的变异系数（CV）在批间为5.45 - 9.22%，批内为1.60 - 4.52%。MN的检测限为2.6微克/升，NMN的检测限为2.微克/升，两种分析物在15.0毫克/升范围内呈线性响应。患者样品的结果与采用双离子交换萃取法的结果相关性良好（MN：r = 0.963，n = 82；NMN：r = 0.9768，n = 83）。该方法具有高选择性和客观的峰纯度信息，同时极大地简化了样品制备。
