Determination of dopamine-O-sulfate and norepinephrine-O-sulfate isomers and serotonin-O-sulfate by high-performance liquid chromatography using dual-electrode electrochemical detection

Abstract

This report describes the use of high-performance liquid chromatography with dual series electrode electrochemical detection to quantitate dopamine (DA)-3-O-sulfate and DA-4-O-sulfate, as well as norepinephrine (NE)-O-sulfate isomers and serotonin (5-HT)-O-sulfate. An oxidation potential was maintained at the upstream (W1) electrode, and a reduction potential at the downstream (W2) electrode. For DA- and NE-sulfates, the sulfate moiety, hydrogen and electrons are most likely removed at W1 and the corresponding quinones formed. At W2, the electrons are recaptured, creating a reductive current (peak). Results indicate that this is a sensitive procedure for the determination of DA- and NE-sulfate isomers. It is less complex than a recently developed post-column hydrolysis procedure, and is at leat equivalent to that procedure in terms of specificity and lower limits of detection (<1 picomole) for the DA- and NE-sulfate isomers. The procedure is relatively insensitive for 5-HT-O-sulfate, as well as for tyramine-O-sulfate, homovanillic acid-sulfate and 3-methoxy-4-hydroxyphenyl glycol sulfate. It should prove useful for investigation concerning the specific conjugates of DA or NE in body tissues and fluids.