Sensitivity and stability improvement on slippery surface-aggregated substrate for trace heavy metals detection using...

Area of Science:

• Analytical Chemistry
• Materials Science
• Spectroscopy

Background:

• Sensitive detection of trace heavy metals in liquids is critical for human health and environmental monitoring.
• Nanoparticle-enhanced laser-induced breakdown spectroscopy (NELIBS) with the dried droplet method (DDM) is a common technique for heavy metal analysis.
• The coffee ring effect (CRE) in DDM negatively impacts the stability, accuracy, and sensitivity of NELIBS.

Purpose of the Study:

• To develop a novel substrate to mitigate the CRE in DDM-NELIBS.
• To enhance analyte enrichment and create a plasmonic platform for improved NELIBS performance.
• To enable sensitive and stable detection of trace heavy metals in liquid samples.

Main Methods:

• Fabrication of a slippery surface-aggregated (SS) substrate by infiltrating perfluorinated lubricant into a PTFE membrane.
• Drying droplets containing target elements and gold nanoparticles on the SS substrate to form a plasmonic platform.
• Analysis of trace copper (Cu) and manganese (Mn) using NELIBS on the developed substrate.

Main Results:

• The SS substrate effectively suppressed the CRE and enriched analytes, leading to stable and sensitive NELIBS detection.
• Achieved low limits of detection (LoD) for Cu (3.72 μg/L) and Mn (6.37 μg/L), meeting China's standard limit (GB/T 14848-2017).
• Demonstrated low relative errors (5.92% for Cu, 4.74% for Mn) in groundwater analysis compared to ICP-MS, validating practical feasibility.

Conclusions:

• The SS substrate is a viable solution for overcoming CRE limitations in DDM-NELIBS.
• This approach significantly improves the stability, accuracy, and sensitivity of heavy metal detection.
• The SS substrate holds substantial potential for practical applications in water quality monitoring and supervision.