An electrochemiluminescence (ECL) array device for the visualized detection of trace Pb2+ was developed, exploiting a Pb2+-specific aptamer DNA chain conjugated to gold nanoparticles (AuNPs) immobilised on an indium tin oxide (ITO) substrate. The sensor achieves an LOD of 9.8 pg/L for Pb2+, which the authors describe as among the most sensitive reported ECL limits for lead. Practical applicability was demonstrated by measuring spiked Pb2+ in extracts of Lycium ruthenicum Murr. (wolfberry), Glycyrrhiza uralensis (licorice root), and lake water.
Key numbers
- LOD: 9.8 pg/L (Pb2+)
- Linear range: 0–10 µg/L
- Selectivity tested against K+, Ca2+, Na+, Mg2+, Sr2+, Hg2+, Fe3+, Cd2+, Cs+, Ag+, Cu2+ at 100 mg/L (Pb2+ at 100 ng/L)
- Recovery in real matrices (spiked): data reported; specific values in supplementary Table S1
- Analytical method validated in Lycium ruthenicum Murr., Glycyrrhiza uralensis, and lake water
Methods (brief)
ECL imaging using Ru(bpy)3Cl2 as luminophore; AuNPs@dsDNA aptamer probe on ITO electrode array. Signal decreases as Pb2+ displaces the NH2-ssDNA strand, reducing ECL intensity. CV and EIS characterisation; PMT at 400 V, scan rate 100 mV/s in 0.1 M PBS pH 7.4. No speciation — measures total aqueous Pb2+. Not an ICP-MS or AAS occurrence study.
Implications
Certification: Not directly applicable for threshold-setting. The paper validates the sensor in wolfberry and licorice root, which are functional-food ingredients occasionally present in herbal formulations and dietary supplements. Courses: Demonstrates portable field-deployable Pb detection at sub-µg/L levels relevant to food safety monitoring. App: Wolfberry and licorice root are uncommon in the app’s product scope; relevance limited to specialty botanical ingredient pages if created.