Improved liquid-chromatographic determination of 3-methoxy-4-hydroxyphenylethyleneglycol in urine with electrochemical detection.

In this improved method for quantifying 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) in urine, after a multistep extraction of MHPG and internal standard (iso-MHPG) from 3.0 mL of urine, the compounds are separated on a C18 reversed-phase column and quantified by use of an electro-chemical detector. The isocratic chromatographic separation takes about 16 min. The mobile phase is phosphate buffer/acetonitrile (88/12 by vol), the flow rate 0.7 mL/min. Recycling the mobile phase and automating the sample injection make possible the unattended assay of more than 70 samples per day. The within-run precision of the method is excellent (CV 1.8%) at a mean concentration of 1.1 mg/L.