Biospecific binding reactants labelled with luminescent lanthanide chelates and their use

A luminescent lanthanide chelate comprising a lanthanide ion and a chelating ligand of the formula ##STR9## characterized in that a) --A-- is a bivalent aromatic structure selected from the group consisting of ##STR10## b) one of the groups G.sub.1 or G.sub.2 is selected from a group consisting of hydrogen, chloro, bromo, iodo, cyano, phenyl, alkyl and alkoxy, with the proviso that said alkyl contains 1-6 carbon atoms;

• and the other group G.sub.1 or G.sub.2 is a substituent which does not participate in the chelating process, which comprises one to four moieties, each moiety being selected from the group consisting of phenylene, alkylene containing 1-8 carbon atoms, ethynediyl (--C.tbd.C--), ether (--O--), thioether (--S--) and amide (--CO--NH-- and --NH--CO--), which additionally contains one moiety selected from a group containing hydroxy, nitro, amino, aminooxy, carboxyl, aldehyde or mercapto groups or an activated form made from them such as isocyanato, isothiocyanato, diazonium, bromoacetamido, iodoacetamido, reactive esters, pyridyl-2-dithio or 6-substituted 4-chloro-1,3,5-triazon-2-ylamino;
• and which is used for coupling to a biospecific binding reactant;
• and
• c) the lanthanide ion is europium(III), terbium(III), dysprosium (III) or samarium (III).

A method of carrying out a biospecific binding assay, comprising binding a detectable molecule to an analyte to be determined, said detectable molecule comprising a biospecific binding reactant attached to a luminescent lanthanide chelate comprising lanthanide ion and a chelating ligand of the formula ##STR11## characterized in that a) --A-- is a bivalent aromatic structure selected from the group consisting of ##STR12## b) one of the groups G.sub.1 or G.sub.2 is selected from a group consisting of hydrogen, chloro, bromo, iodo, cyano, phenyl, alkyl and alkoxy, with the proviso that said alkyl contains 1-6 carbon atoms;

• and the other group G.sub.1 or G.sub.2 is a bridge which does not participate in the chelating process and which comprises one to four moieties, each moiety being selected from the group consisting of phenylene, alkylene containing 1-8 carbon atoms, ethynediyl (--C.tbd.C--), ether (--O--), thioether (--S--) and amide (--CO--NH-- and --NH--CO--);
• and which is used for coupling to the biospecific binding reactant via thiourea (--NH--CS--NH--), aminoacetamide (--NH--CO--CH.sub.2 --NH--), amide (--NH--CO-- and --CO--NH--), aliphatic thioether (--S--), disulfide (--S--S--) or 6-substituted-1,3,5-triazine-2,4-diamine;
• and
• c) the lanthanide ion is europium(III), terbium(III), dysprosium (III) or samarium (III).