Abstract
Pulsed electrochemical detection (PED) is applied to alkanolamines separated by high-performance liquid chromatography (HPLC). A multimodal HPLC column with both cation-exchange and reversed-phase retention modes is used with an acidic mobile phase to assure alkanolamines are in their cationic form. Baseline resolution of alkanolamines, including positional isomers, is possible. Detector response for a representative alkanolamine, tris(hydroxymethyl)aminomethane (Tris), is shown to be linear over a concentration range of more than three decades. The limit of detection for Tris is 20 n
M (500 fmol in a 25-μl injection) and the standard deviation of the PED response for 10
μM Tris is better than 0.4%. HPLC-PED is demonstrated to permit the sensitive and precise determination of alkanolamines in a biological sample (blood) and a commercial formulation (shaving gel) with minimal sample preparation.