Gas-liquid chromatographic method for routine detection of plasma sulfo-, gluco-, and free 3-methoxy-4-hydroxyphenylglycol

A revised method is described for detection of human plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) using gas-liquid chromatography and electron capture detection. This method has comparable sensitivity and reproducibility as HPLC methods with amperometric detection but is less expensive. The extraction and detection of an internal standard of 3-ethoxy-4-hydroxyphenylglycol (EHPG) is identical to MHPG, making quantitation easier than with electrochemical detection. Techniques for measuring the sulfo-, gluco-, and free plasma MHPG fractions are described, and normal adult values are reported.