Fluorescence enhancement of terbium(III) by nucleotides and polyhomonucleotides in the presence of phenanthroline

Abstract

The fluorescence enhancement of terbium(III) by nucleotides (AMP, ADP, ATP, GMP, GDP, GTP) and polyhomonucleotides [poly(A), poly(G), poly(C), poly(U)] in the presence of phenanthroline (phen) was studied. Investigation of the composition of the terbium(III)/ANP(AMP, ADP, ATP)/phen complexes and conditions of optimization suggest a 1:2 molar ratio of terbium(III) and phen for the ternary complexes. The results showed that the presence of phen enhanced the net fluorescence of terbium(III)/ANP, poly(A), poly(C) or poly(U) from several fold to more than one-hundred fold, while it has little effect on the fluorescence of terbium(III)/GNP(GMP, GDP and GTP) or the poly(G) system. The possibility of spectrofluorimetric measurements of these compounds were studied under optimal conditions (pH 7.0 in tris-HCl buffer; Ex=298 nm, Em=543.5 nm). The detection limits were 2.0×10−7, 6.0×10−7 and 1.0×10−6 mol/l for AMP, ADP and ATP, respectively. The relative standard deviations (6 replicates) were within 2.0% in the middle of the linear range.