Flood J G, Granger M, McComb R B
Clin Chem. 1979 Jul;25(7):1234-8.
We describe a method for measurement of 3-methoxy-4-hydroxymandelic acid (vanillylmandelic acid, VMA) in urine. After the pH of the urine is adjusted to 2.7 and the sample is filtered, exactly 15 microL is injected onto a C-18 reversed-phase column. VMA is eluted from the column with 10 mmol/L phosphate buffer, pH 2.7, containing 30 mL of acetonitrile per liter. The eluate stream is combined with alkaline periodate and then passed through a 60 degrees C water bath. The VMA is completely oxidized to vanillin, which is detected and quantitiated by its absorbance at 360 nm. No deterioration of the column was noted after 167 such injections of urine samples. Long-term control data indicate a CV of 12 and 10% at VMA concentrations of 1.5 and 5.8 mg/L, respectively. Although results correlate well (r = 0.976) with those by the method of Pisano et al. [Clin. Chim. Acta 7, 285 (1962)], they average 10% lower. Of 20 compounds tested, only methyl dopa interfered with the procedure as described.
我们描述了一种测定尿中3-甲氧基-4-羟基扁桃酸（香草扁桃酸，VMA）的方法。将尿液pH值调至2.7并过滤样品后，准确吸取15微升注入C-18反相柱。用每升含30毫升乙腈的pH 2.7的10毫摩尔/升磷酸盐缓冲液从柱上洗脱VMA。洗脱液与碱性高碘酸盐混合，然后通过60℃水浴。VMA完全氧化为香草醛，通过其在360纳米处的吸光度进行检测和定量。在对尿样进行167次这样的进样后，未发现柱性能变差。长期对照数据表明，在VMA浓度分别为1.5和5.8毫克/升时，变异系数分别为12%和10%。尽管结果与皮萨诺等人[《临床化学学报》7, 285 (1962)]的方法相关性良好（r = 0.976），但平均低10%。在所测试的20种化合物中，只有甲基多巴会干扰所述的检测程序。
