Determination ofN-nitrosamines by HPTLC with fluorescence detection — Use of non-ionic surfactants as enhancing agents

The dansyl derivatives of N -nitrosodimethylamine, N -nitrosodiethylamine, and N -nitrosodibuthylamine have been separated by HPTLC with silica gel as stationary phase and hexane-diethyl ether-dichloromethane, 10 + 3 + 2 ( v/v ) as mobile phase. A fiber-optic-based fluorescence instrument for in-situ scanning was used for quantitative measurements. The effects of non-ionic surfactants as agents for enhancing the fluorescence intensity of dansyl derivatives of N -nitrosamines in HPTLC were investigated by dipping the plates in a mixture of the surfactant and a volatile organic solvent. It was shown that the presence of polyoxyethylene-10-lauryl ether enhances both the fluorescence intensity and the signal-to-noise ratio of the dansyl derivatives. The detection limits, which ranged between 0.47 and 0.89 ng, were five times lower than those obtained in the absence of surfactant.