Simultaneous quantitative measurements of Tl⁺ and Pb²⁺ in drinking water based on nanoplasmonic probe

Rapid and precise detection of Tl⁺ and Pb²⁺ is important to prevent water poisoning and environmental pollution. Gold nanoparticles (AuNPs) have gained focus for heavy metal ion detection but cannot yet achieve accurate quantitative analyses when Tl⁺ and Pb²⁺ coexist. We propose a sensitive, flexible, and low-cost method for the qualitative and quantitative analysis of binary Tl⁺/Pb²⁺ mixtures based on AuNP sensors. Partial least squares, back interval partial least squares and data fusion applied to analyze UV-Vis spectral data according to the AuNPs aggregation behavior, revealed discrete responses to the target analytes. The limits of detection for Tl⁺ and Pb²⁺ in the binary mixture were 5.23 and 1.76 nM, respectively, and good linear dependence was obtained. The method was successfully applied to the detection of both ions in tap and mineral water. This method can reveal water poisoning and environmental pollution events to ensure drinking water safety.