Capillary electrophoresis determination of biogenic amines by field-amplified sample stacking and in-capillary derivatization

A sensitive CE method for determining biogenic amines in wines based on in-capillary derivatization with 1,2-naphthoquinone-4-sulfonate is presented. In this method, reagent and buffer solutions are introduced hydrodynamically into the capillary whereas the sample is injected electrokinetically, thus, allowing a selective pre-concentration of the analytes by field-amplified sample stacking. Amines are labeled inside the capillary using a zone-passing derivatization approach in mixed tandem mode. The most relevant variables influencing on the derivatization and separation as well as significant interactions have been evaluated using experimental design. Multi-criteria decision making is utilized for the simultaneous optimization of interacting variables through overall desirability response surfaces. The validation of the method has proven an excellent separation performance and accuracy for the determination of biogenic amines such as histamine, tryptamine, phenylethylamine, tyramine, agmatine, ethanolamine, serotonin, cadaverine, and putrescine in red wines. Detection limits range from 0.02 mg/L for ethanolamine to 0.91 mg/L for serotonin. The RSDs for migration time and peak area are around 1.2 and 6.2%, respectively. Red wines from different Spanish regions have been analyzed using the proposed method.