Chemiluminescence determination of guanine and its nucleosides and nucleotides using phenylglyoxal

Abstract A novel chemiluminescence method is described for the determination of guanine and its nucleosides and nucleotides. The method is based on the fluorescence reaction of the substances with phenylglyoxal in a phosphate buffer (pH 6.0) at 37°C for 20 min, followed by a chemiluminescence reaction with N,N -dimethylformamide in a weakly alkaline medium. The established conditions of the chemiluminescence reaction do not permit any development of chemiluminescence from other nucleic acid bases such as adenine, cytosine, uracil and thymine, and their nucleos(t)ides. This method is quite selective and approximately 20-fold more sensitive than the fluorimetric one; the detection limits for guanine nucleos(t)ides are 4–19 pmol ml −1 in the reaction mixture.