Eu-Coordinated Semiconducting Polymer Nanoparticles As A Novel Nanoprobe With Two Detection Method Signals For Determination Of Copper (Ii) Ions

Eu-coordinated semiconducting polymer nanoparticles (SPNs-Eu) were developed for bimodal analysis of copper (II) ions (Cu2+) over a wide dynamic range (mu M to pM). In this sensing system, the first readout mode is based on the fluorescence signal of SPNs-Eu. A significant quenching of the fluorophore is selective for the presence of Cu2+ due to the aggregation of SPNs-Eu. The aggregations are caused by chelation of Cu2+ with carboxylate groups on SPNs-Eu and the amount of aggregation can be quantified by the 153Eu signal of SPNs-Eu using singleparticle inductively coupled plasma mass spectrometry (sp-ICPMS). This signal is the second readout mode of these nanoparticles, which can be calibrated for sub-pM determination of Cu2+. Compared with the monodisperse SPNs-Eu reagent, aggregation in the presence of Cu2+ significantly decreases the number of detected particles or particle clusters within a sampling period of the sp-ICPMS measurement. The fluorescence readout yields a facile and rapid detection method with a rather limited linear range from 2 mu M to 50 mu M and a limit of detection (LOD) of 0.29 mu M. In contrast, the sp-ICPMS readout provides a far more sensitive analysis method with a linear range from 1 pM to 10 mu M and a LOD of 0.42 pM.