Compositional analysis of soil using calibration-free laser-induced breakdown spectroscopy

Compositional analysis often soil samples collected from Islamabad, Pakistan, is performed using the fundamental harmonic (1064nm) of a Q-switched Neodymium-doped Yttrium Aluminum Garnet (Nd:YAG) laser. The plasma emissions were recorded using a broadband (200-800 nm) spectrometer (LIBS2500plus, Ocean Optics Inc., USA) having approximate to 0.1 nm resolution. The qualitative analysis of the pelletized soil samples confirms the presence of several heavy metals (Titanium, Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Lead, Copper, Zinc, Cadmium, Zirconium, Cesium, Strontium, and Barium), light and nutrients elements (Lithium, Rubidium, Aluminum, Boron, Carbon, Potassium, Nitrogen, Magnesium, Phosphorus, Silicon, and Calcium). The quantitative analyses were performed using the calibration-free laser-induced breakdown spectroscopy, its variant, and single sample calibration techniques. It is found that the concentration of heavy metals (Cadmium, Cobalt, Chromium, and Nickel) exceeds the maximum permissible limit, which is eventually accumulated in the human body through the food chain and threatens health.