Comparison of the solid-matrix luminescence properties of benzo(a)pyrene-DNA adducts on alpha-cyclodextrin/NaCl and trehalose/NaCl matrices.

Abstract

The solid-matrix luminescence properties of (+/-)-trans-7,8-dihydroxy-anti-9, 10-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene-DNA ([+/-]-anti-BPDE-DNA) adducts were compared on alpha-cyclodextrin (CD)/NaCl and trehalose/NaCl solid matrices. Both the optimum composition for the solid matrices and the best solvent system were obtained experimentally for acquiring the maximum room-temperature fluorescence (RTF) and room-temperature phosphorescence (RTP) signals for the (+/-)-anti-BPDE-DNA. Most of the solid-matrix RTF and RTP data were obtained at 296 K and 93 K for (+/-)-anti-BPDE-DNA adducts adsorbed on 1% alpha-CD/NaCl and 80% trehalose/NaCl. The RTF signals were strong for (+/-)-BPDE-DNA adducts on both solid matrices, but RTP was only obtained on the trehalose/NaCl solid matrices with the 80% trehalose yielding the strongest RTP signal for (+/-)-anti-BPDE-DNA. The fluorescence lifetime data for (+/-)-anti-BPDE-DNA gave two components on 1% alpha-CD/NaCl. For 80% trehalose/NaCl, three components were revealed, but two components were obtained with 80% trehalose/NaCl after ether extraction of the solid matrix. The third component was ascribed to the formation of the tetrols from (+/-)-anti-BPDE-DNA adducts during the drying step in the sample preparation of 80% trehalose/NaCl. The results give the first reported data on the solid-matrix luminescence of the (+/-)-anti-BPDE-DNA adducts. These results should be of considerable interest not only from an analytical viewpoint but as a new means of studying the luminescence characteristics of the adducts.