Comparison of sieving matrices for on-the-fly fluorescence lifetime detection of dye-labeled DNA fragments

Commercially available, replaceable sieving matrices and their solvent modu lated forms were evaluated for use in on-the-fly fluorescence lifetime dete ction of dye-labeled DNA fragments in capillary electrophoresis. The fragme nts were labeled with dyes that can be excited by the 488 nm line of an arg on ion laser and have lifetimes in the range of 0.8 ns to 3.8 ns. The sievi ng matrices and buffer systems included poly(vinylpyrrolidone) (PVP), poly( ethyleneoxide) (PEO), hydroxyethylcellulose (HEC), Tris-borate-EDTA (TBE an d Tris-TAPS-EDTA buffers modified with DMSO and formamide. Selection of the optimal sieving matrix is based on the separation efficiency and the enhan cement of lifetime resolution of DNA fragments. Best results for both elect rophoretic resolution and lifetime detection were obtained using a poly(eth yleneoxide)/TBE gel buffer in the presence of 10% formamide.