Determination of polyamines by capillary electrophoresis using salicylaldehyde-5-sulfonate as a derivatizing reagent

Here we describe a protocol for the determination of polyamines using capillary electrophoresis with ultraviolet absorbance detection. Aliphatic polyamines were derivatized with salicylaldehyde-5-sulfonate (SAS) which formed Schiff base with amino groups, resulting in anionic derivatives. The derivatization of polyamines, including putrescine (PUT), cadaverine (CAD), spermidine (SPD), and spermine (SPM), was conducted in 10 mM HEPES buffer with pH 7.8 containing 5 mM SAS in a mixed solvent of water and ethanol. The SAS derivatives were separated using a background electrolyte composed of 10mMphosphate buffer with pH 7.8. Calibration curves were linear over a concentration range of 20–200 μM for CAD, PUT, SPD, and SPM, and the limits of detection (LOD) were several μM for all polyamines. Furthermore, solid phase extraction was coupled with the CE method to improve the LOD to sub-μM levels, and the calibration curves were linear over a concentration range of 1–20 μM for CAD, PUT, and SPD.