Method of chemical analysis employing molecular release tag compounds

In an assay which includes contacting an analyte-containing sample with a labeled reagent, or with a conjugate made by covalently reacting a labeled reagent with an analog of, ligand for, or specific binding partner of said analyte, incubating, and measuring the amount of label, the improvement which comprises:

• using as the labeled reagent a release tag compound, S-Re-Rx, wherein S is a signal group covalently bound to group Re, and Re is a cleavable release group which is covalently bound to group Rx which is a reactivity group;
• and S is further defined as comprising a halogenated electron-absorbing group which can be measured by electron capture detection;
• and Re is further defined as comprising a functionality selected from the group consisting of disulfides, tryptophan, tyrosine, thioesters, azo compounds, p-toluenesulfonic esters of .beta.,.gamma.-acetylenic alcohols, alkyl phenyl ethers, hydrazones, thioethers, benzoyloxycarbonylamines, alkylsulfonylethoxycarbonylamines, arylsulfonylethoxycarbonylamines, alkylthioethyloxycarbonylamines, arlythioethyloxycarbonylamines, tosylamines, S-benzylethers, o-nitrobenzylamides, 2-nitro-4,5-dimethoxy-benzyloxycarbonylamines, amine oxides, and xanthates, and is capable of releasing the signal group in a volatile form suitable for measuring by electron capture detection;
• and Rx is further defined as comprising a functional group which is capable of forming a covalent bond with the analyte to be detected, or with an analog of, ligand for, or specific binding partner of said analyte.

In an assay which includes contacting an analyte-containing sample with a labeled reagent, or with a conjugate made by covalently reacting a labeled reagent with an analog of, ligand for, or specific binding partner of said analyte, incubating, and measuring the amount of label, the improvement which comprises:

• using as the labeled reagent a release tag compound, S-Re-Rx, wherein S is a signal group covalently bound to group Re, and Re is a cleavable release group which is covalently bound to group Rx which is a reactivity group;
• and S is further defined as comprising a halogenated electron-absorbing group which can be measured by electron capture detection;
• and Re is further defined as comprising a functionality selected from the group consisting of methionylamides, vicinal glycols, olefins, .gamma.-phenylethylamine oxides and benzyl ethers, and is capable of releasing the signal group in a volatile form suitable for measuring by electron capture detection;
• and Rx is further defined as comprising a functional group which is capable of forming a covalent bond with the analyte to be detected, or with an analog of, ligand for, or specific binding partner of said analyte;
• cleaving said release group to free said signal group;
• and measuring said free signal group.