Effect of non-ionic surfactants as mobile phase additives on the fluorescence intensity of dansyl derivatives of biogenic amines in high-performance thin-layer chromatography

The effects of non-ionic surfactants as mobile phase additives on the fluorescence intensity of dansyl derivatives of biogenic amines in high-performance thin-layer chromatography (HPTLC) were investigated. The dansyl derivatives of putrescine, cadaverine, spermidine and spermine were separated by HPTLC with silica gel as stationary phase and an eluent consisting of chloroform–triethylamine (2 + 1 v/v) containing 5% m/v of polyoxyethylene-10-lauryl ether (POLE). A fibre-optic-based fluorescence instrument for in situ scanning was used for quantitative measurements. The compounds were determined over the range 0.5–85 ng, with relative standard deviations between 0.44 and 1.16% and detection limits in the range 0.28–0.39 ng. It is shown that the presence of POLE in the mobile phase enhances both the fluorescence intensity and the signal-to-noise ratio of the chromatographed dansyl derivatives. The method was applied to the determination of biogenic amines in plant tissue and beer samples.