Determination of Micronutrients and Toxic Elements in Moringa Oleifera Leaves by Calibration Free Laser-Induced Breakdown Spectroscopy (LIBS)

Abstract

The Moringa oleifera tree, including the leaves, flowers, pods, and seeds, is highly nutritious and useful for the prevention and control of various diseases. Here we have probed the micronutrients in Moringa oleifera leaves using laser-induced breakdown spectroscopy (LIBS). The time-resolved and time-integrated LIBS data reveal the presence of Ca, Mg, K, C, Si, Fe, Al, Ti, Sr, Na, H, O, and Li. The plasma temperature and electron number density required for the elemental composition analysis were estimated to be (6375 ± 500) K from the Saha-Boltzmann plot and (1.0 ± 0.2) 1017 cm−3 from the Stark broadened Hα line, respectively. Elemental analysis of the samples was performed using one-line calibration free LIBS (CF-LIBS). The results reveal that C is the major element together with Ca, Mg, K, Fe Na, Al, Ti, Sr, and Li as micronutrients. The concentrations of the micronutrients determined by CF-LIBS were validated by inductively coupled plasma – optical emission spectrometry (ICP-OES). LIBS has been demonstrated to be a practical candidate for the detection of potentially toxic elements (Li, Al, Si, and Sr) as well as for the compositional analysis.