Elemental and molecular detection for Quantum Dots-based immunoassays: A critical appraisal

► Critical comparison between molecular fluorescence and Elemental Mass Spectrometry (ICP-MS) techniques for QDs-based immunoassays. ► Important improvement on the detection limits for progesterone determination in cow milk using ICP-MS. ► ICP-MS mass balances information provided an internal validation of the immunoassay procedure. ► ICP-MS matrix-independent quantification enabled a direct sample analysis avoiding any dilution step. ► Better precision obtained using Fluorescence than ICP-MS (strongly limited by procedural blanks).