Advancing Environmental Monitoring: Unveiling Heavy Metal Contamination with Calibration-Free Picosecond Laser-Induced Breakdown Spectroscopy (CF-PS-LIBS)

Abstract

Abstract Elevated concentrations of heavy metals in environmental matrices are linked to substantial toxicity hazards, impacting human health and ecosystem wellbeing. In this research, Calibration-Free Picosecond Laser-Induced Breakdown Spectroscopy (CF-PS-LIBS) is introduced for determining concentrations of Fe, Zn, Mn, Ni, Pb, and Cr in the roots and shoots of clover plants collected from villages in the Banha and Giza governorates of Egypt. CF-PS-LIBS spectra, generated by a 1064 nm Q-switched Nd: YAG laser with a pulse width of 170 ps and energy of 100 ± 5% J/cm², are analyzed to assess heavy metal content. The study leverages emission intensity and broadening associated with the Ca I characteristic lines at specified wavelengths to provide insights into plasma evolution. Linear variations in electron temperature (Te) and electron density (Ne) are observed in samples with heavy metal concentrations ranging from 0.11 to 0.17 mg/kg for Cr and 429.03 to 2259.51 mg/kg for Fe. Plasma Te escalates from approximately 6696.062 to 8957.761 K, while Ne increases from 0.914 × 10¹⁷ to 2.63 × 10¹⁷ cm⁻³. These Te and Ne fluctuations are distinctive markers for plasma characterization relative to specific heavy metal concentrations in clover samples. The application of CF-PS-LIBS is highlighted as a novel advancement in environmental monitoring, offering enhanced accuracy in spectrochemical analyses and contributing to developing effective remediation strategies for areas affected by heavy metal contamination.