Elemental Composition of Moringa Oleifera Lam Seeds Using Calibration Free Laser Induced Breakdown Spectroscopy (CF-LIBS)

Abstract

For centuries, medicinal plants have been widely used to treat numerous diseases. Given the extensive application of Moringa Oleifera Lam. in medicine, it is essential to understand its beneficial medicinal properties as well as any potentially toxic elements. In this study, we performed Laser-Induced Breakdown Spectroscopy (LIBS) analysis on Moringa oleifera Lam. seeds using a Neodymium-doped Yttrium Aluminium Garnet (ND: YAG) laser in ambient air at varying energies and delay times. Using LIBS, we determined the elemental composition of the seeds and quantified the concentrations of the observed elements via the Calibration-Free (CF)-LIBS technique. The analysis revealed the presence of carbon (C), calcium (Ca), sodium (Na), magnesium (Mg), iron (Fe), potassium (K), aluminium (Al), strontium (Sr), silicon (Si), chromium (Cr), and lithium (Li), along with a molecular CN band. Among these, C, Ca, Na, Mg, Fe, and K were identified as major elements due to their higher concentrations, whereas Sr, Cr, Li, and Al were present in trace amounts. Additionally, we detected a well-defined H-alpha emission line. By analyzing the Stark-broadened line of calcium at 245.38 nm, we estimated the plasma temperature. The electron number density was computed using the Boltzmann plot method based on neutral calcium lines. Finally, we assessed the validity of the Local Thermodynamic Equilibrium (LTE) condition in the plasma.