Patent ID: 7485424

Claim:
A method of identifying a nucleotide incorporated in a nascent strand in a nucleic acid polymerization reaction, comprising: providing an individual complex of a nucleic acid polymerase, a target polynucleotide and a primer that hybridizes to the target polynucleotide, positioned within a confined focal volume provided on a support; introducing at least a first nucleotide or nucleotide analog bearing a first fluorescent label into the focal volume; measuring a residence time of the at least first nucleotide or nucleotide analog within the focal volume, wherein the residence time of the at least first nucleotide or nucleotide analog is reflected by a period of duration of a fluorescence signal from the first fluorescent label in the focal volume, said period being longer than that of an unincorporated nucleotide or nucleotide analog randomly diffusing through the focal volume, thereby identifying a nucleotide incorporated by the polymerase of said individual complex in the nucleic acid polymerization reaction based upon the residence time of the nucleotide or nucleotide analog within said focal volume.