<prompt> Radio isotopes are used in the following techniques except:Mass spectroscopyRIAELISASequencing of nucleic acid  <response>: C i.e. ELISA Concept: ELISA Enzyme Linked Inununoabsorbent Assay is an enzyme based immnoassy; the similar test which uses radioactive isotope in place of enzyme is known as Radioimmunoassay RIA So I dont think any need of learning that- Nucleic acid sequencing, mass spectroscopy RIA are tests using radio isotopes. 