Efficient Heavy Metals Detection in Plants: A Microfluidic Approach Combined with Laser-Induced Breakdown Spectroscopy

The detection of heavy metals (HMs) in plants is essential for ensuring the health of both plants and humans. Nevertheless, existing detection techniques are limited by high costs and their potential to damage plant samples. In this paper, a wearable paper-based microfluidic sap enrichment (PMSE) device combined with laser-induced breakdown spectroscopy (LIBS) is presented. Colorimetric analysis was employed to optimize critical parameters of the HM-enrichment filter paper, including its diameter and pore size, ensuring efficient and uniform HM accumulation. The CuNPs-modified filter paper effectively enriched HMs and enhanced LIBS signals, enabling the detection of Cd(II) and Pb(II) in cucumber plants across a concentration range of 0–150 ppb. The method achieved detection limits of 3 ppb for Cd(II) and 5 ppb for Pb(II). This study provides a theoretical basis and technical support for the rapid detection of heavy metals in plants.