Efficient and Fast Purification Method for Fluorescent Dye-Labeled Oligonucleotides

Fluorescent dye labelling is an essential and general procedure in Biophysics. Especially in single-molecule spectroscopy, labeling the oligonucleotides with fluorescent dyes and purifying the excess to enhance the signal-to-noise ratio are unavoidable. Common purification methods such as gel filtration, ethanol precipitation and HPLC consume large amounts of time and cause a huge sample loss. In order to improve the efficiency and to simplify the procedure of removing the unlabeled free dyes, here we introduce a new purification method. Through this new method the labeled oligonucleotides and the unlabeled free dyes can be separated and purified by pH-control. This innovative method is easy, fast and efficient which is applicable to various classes of dyes regardless of charge, size and structure with a high recovery yield and purification result.