Lead(II)-triggered aggregation-induced emission enhancement of adenosine-stabilized gold nanoclusters for enhancing photoluminescence detection of nabam-disodium ethylenebis(dithiocarbamate)

Developing a rapid, efficient, sensitive and selective nabam sensor is essential due to its potential effect on human toxicity and environmental risk. In the report, a fast, ultrasensitive and highly selective sensor for the detection of nabam-disodium ethylenebis(dithiocarbamate) is developed using lead(II)-triggered photoluminescent aggregated gold nanoclusters (AuPbNCs) as probes. The AuPbNCs are synthesized using chloroauric acid, lead(II) acetate basic, and adenosine as the precursors. Detailed characterizations confirm that during the synthesis process of AuPbNCs, lead(II) precursor not only acts as a coupling agent to induce the aggregation of nanoclusters, but also serves as a dopant into nanoclusters. Relative to the photoluminescent adenosine-stabilized gold nanoclusters (AuNCs), AuPbNCs exhibit emission enhancement behavior, ascribing to the structural rigidification and heavy-atom effect of lead. Nabam induces photoluminescence quenching of AuPbNCs, and the quenching process is predominately attributed to static photoinduced electron transfer. A linear relationship with two segments between the photoluminescence quenching ratio of AuPbNCs and nabam concentrations ranging from 0.05 to 25 nM is established, and the detection limit of 20 pM is achieved on the basis of a signal-to-noise (S/N) ratio of 3. Compared with the AuNCs, the highly photoluminescent AuPbNCs exhibit enhanced sensitivity and selectivity for nabam detection. The interaction study between nabam and AuPbNCs reveals that when the added nabam concentration increases, AuPbNCs undergo a process, from aggregation to disaggregation, and then to reaggregation, due to the complexation between nabam and lead or gold of the AuPbNCs. Moreover, the AuPbNCs-based sensor is successfully tested for the nabam detection in real samples (lake water and wheat) and test papers.