A simple and rapid method for the determination of 4-hydroxy-3-methoxymandelic acid (HMMA) in urine

A simple and rapid method for the determination of urinary 4-hydroxy-3-methoxymandelic acid (HMMA) using Dowex resin is outlined. The HMMA is measured as a colour complex with diazotised p-nitroaniline. The method also allows for the determination of high HMMA levels as well as repeat estimations from the eluate which can then be completed within 20 min. An average of six estimations can be done by one technician within 3 h. Repeatability is good and good correlation is found when compared with the method of Pisano. We have found the proposed method to be suitable for routine work.