Rapid qualitative and quantitative vital nutrient contents in high-altitude cultivated folklore herbal medicinal Costus roots using calibration-free LIBS

Costus Roots (CRs) (Saussurea lappa C.B. Clark- Asteraceae family) is a medicinal herb, very frequently utilized in developing countries for treating worm (nematode) infections, asthma, cholera, digestive problems and in cosmetics products. Due to its widespread consumption in developing countries to determine the health-related essential nutrients and toxic elements is of great significance. This study is highly noteworthy for prominence of therapeutic benefits of the CR roots and public awareness about their harmful effects even for producing herbal drugs derived from its roots. In this study, a very efficient, precise and rapid laser-induced breakdown spectroscopy (LIBS) method was developed to measure the content of the dried and pelletized CRs powder samples. To the best of our knowledge, this is first time that Costus roots have been studied using calibration-free LIBS (CF-LIBS) technique. Initially, the LIBS spectrometer parameters were optimized at 608.3 nm gated-time delay, 35 mJ incident laser pulse energy, and 29 mm laser-to-sample distance (LTSD)) for precise element detection before its application to the CRs analysis. The primary focus of this study is the identification and quantification of various nutrients, such as Ca, K, Mg, Si, S, P, Fe, and Na, as well as relatively toxic elements, such as Al, Ba, Mn, Zn, Sr, B, Cu, Rb, Cr, Ni, Pb, V, and Mo, in addition to Li, Ti in this native CRs herbal medicine. The concentrations of these detected elements (Ca, K, Mg, Si, S, P, Al, Fe, Na, Ti, Ba, Mn, Zn, Sr, B, Cu, Rb, Cr, Ni, Pb, V, Mo, and Li) were successfully determined as 14424, 9511, 2031, 1559, 1450, 1465, 678, 458, 59, 48, 47, 37, 37, 27, 19, 19.6, 15, 2.6, 1.5, 1.5, 1.2, 1.0 and 0.9 mg.kg⁻¹ respectively which was in a excellent agreement with the concentrations measured using the standard ICP-OES technique.