On the coupling of fluorescence line-narrowing spectroscopy and poly(ethylene)imine-cellulose thin-layer chromatography

The feasibility of a direct coupling of the low-temperature, high-resolutio n, fluorescence line-narrowing spectroscopy (FLNS) technique and the autora diographic P-32-post-labelling technique for DNA adducts is explored. FLNS has been used to identify analytes on various types of thin-layer chromatog raphy (TLC) plates, but not on poly(ethylene)imine-cellulose (PEI-cellulose ) TLC sheets involved in the P-32-post-labelling technique which includes a two-dimensional separation. PEI-cellulose was found to exhibit a high fluo rescence background. Its fluorescence excitation and emission characteristi cs were studied in detail and the signal-to-noise ratios of the FLNS spectr a were optimized using background subtraction, time-resolved detection and a new synchronous scanning procedure. Benzo[a]pyrene (B[a]P) tetrols and a standard B[a]P-DNA adduct were used as model compounds. Limits of detection were in the low-picomole range. The technique was applied for the identifi cation of spots extracted from PEI-cellulose TLC sheets obtained after a P- 32-post-labelling procedure of DNA containing B[a]P adducts at a level of t wo adducts per hundred bases. (C)2000 Elsevier Science B.V. All rights rese rved.