Novel chemical compounds, with application in fluorometric analytical methods, for qualitative and quantitative determination of biomolecules. The aim of the invention is to identify and prove the suitability of such compounds. Said aim is achieved with compounds of formula (1) where R1 is an antenna function, R2 is a chelate forming agent, containing a coordinated lanthanide(III)ion, X is —OH or a group with affinity for the biomolecule, bonded to a carboxylate group of the chelate forming agent by means of an amide bond and Y is —H or a group with affinity for the biomolecule, coupled to the antenna function.