Element tags based on novel
metal-
polymer conjugates are provided for
elemental analysis of analytes, including ICP-MS. A
polymer backbone is functionalized to irreversibly bind metals that are selected prior to use by the user. The
polymer is further functionalized to attach a
linker which allows for attachment to antibodies or other affinity reagents. The polymer format allows attachment of many copies of a given
isotope, which linearly improves sensitivity. The
metal-polymer conjugate tags enable multiplexed
assay in two formats: bulk
assay, where the average biomarker distribution in the sample is diagnostic, and single
cell format to distinguish a rare (for example a diseased)
cell in a complex sample (for example, blood).