An assay employing a tracer comprising a ligand having a mercury label wherein mercury label is released from at least one of a bound or free tracer phase and interacts with a metal. Analyte is determined by a change in at least one property of the metal caused by such interaction. The invention also...http://www.google.es/patents/US5047044?utm_source=gb-gplus-sharePatente US5047044 - Medical droplet whole blood and like monitoring
