Analysis of Mineral Elements in Medicinal Plant Samples Using LIBS and ICP-OES

Abstract

Laser-induced breakdown spectroscopy (LIBS) was applied for the rapid analysis of the major and trace elements in five medicinal plant samples. The LIBS results showed the presence of carbon, iron, magnesium, silicon, calcium, oxygen, hydrogen, nitrogen and sodium; however, the concentration of these elements differs in each of the five medicinal plant samples. The plant body samples, such as roots and leaves, were first analyzed for the presence of major and trace elements by using the LIBS technique, then their corresponding concentrations were evaluated by applying the intensity ratio method on the observed LIBS data. The results obtained were compared with the intensity ratios obtained from the analysis by inductively coupled plasma-optical emission spectrometry (ICP-OES). Partial least squares-discriminant analysis (PLS-DA) was also performed with the LIBS spectra to extract the spectral differences between the five medicinal plant samples. These statistical methods generate calibration and classification models which can further help to understand the unknown plant sample in the prepared model to predict the nature and the composition of the sample easily in the future. This study clearly shows the LIBS technique, when used with chemometric methods, becomes an important tool to study the distinguishing characteristics of different biological plant samples.