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).