Post-column derivatization capillary electrochromatography for detection of biogenic amines in tuna-meat

A system to perform post-column derivatization capillary electrochromatography (CEC) was developed for the first time. The system mainly included a 4-microm (O.D.) silica packed column (200 mm effective length x 0.1 mm inner diameter I.D.) with micro-magnetic particles (MMPs) frits, a T-junction connector, an in-line fluorescence detector and a high-voltage power supply. The system was evaluated by using histamine (HA) as a standard biogenic amine for this study. A 5 microM HA solution was loaded at the anodic site of the capillary column by applying 3 kV for 5s. Then, HA was electrophoretically eluted with a 20mM phosphate buffer (pH 7) by applying 3 kV, and was derivatized with 3mM o-phthalaldehyde (OPA)/N-acetylcysteine (NAC) in 100 mM borate (pH 10), which was continuously delivered through the reagent-loading capillary tube by gravity into the T-junction connector. HA derivative was finally detected with the in-line fluorescence detector (lambda(Ex)=340 nm, lambda(Em)=450 nm) at 9.7 min after sample loading. To test the utility of this system, it was next employed for its ability to detect the presence of HA and other kinds of biogenic amines, including cadaverine (Cad), spermidine (Spm) and tyramine (Tyr) in tuna-meat, once the validity of the method had been confirmed.