Improving the analytical performance of a phosphorescent nanosensor by optimizing a ratiometric technique

Parasitic emissions arising from the use of a deep UV LED, as well as light scattering caused by the bubbles in the flow system, have been observed. Both phenomena drastically limits the actual applicability of the sensor for real sample analysis. To overcome such problems, a dynamic ratiometric method has been implemented. It is based on linking the analyte-dependent phosphorescent signal and a fluorescent reference signal. The optimal frequencies necessary to modulate the LED have been theoretically deduced and experimentally validated. The results confirm that the proposed solution eliminates the main problems observed, making it possible enhancing and improving the optosensor analytical performance.