LIBS technique evaluation for Ca, K, P and N determination in new smart sustainable fertilizers

Abstract

Fertilizers are important for increasing agricultural productivity, though many losses of fertilizers applied are observed. Such losses increase the cost of productivity and contribute to the accumulation of nutrients in terrestrial and aquatic ecosystems, causing environmental problems. In order to take full advantage of fertilizers, some investigations have been conducted towards the achievement of gradual nutrients release fertilizers. Ongoing research in the Thermal Analysis Laboratory of the Chemistry Institute of Araraquara - UNESP, have indicated the possibility of getting a new fertilizer for nutrient gradual release, which should be produced with biochar, a sustainable material. In the fertilizer evaluation context, it is essential for characterization, the quantitative determination of nutrient elements effectively incorporated into the material during the production process, as well as evaluating the nutrients release. Accordingly, analytical methods that provide a rapid and direct sample analysis may contribute more efficiently with the material characterization and consequently with its development. The Laser-Induced Breakdown Spectroscopy (LIBS) is an analytical technique that allows to evaluate the elemental composition of a sample, in few seconds, from material direct analysis. However, the development of quantitative methods using LIBS require the evaluation of several parameters, particularly the intrinsic barriers related to the calibration. Thus, this proposal aims to evaluate the LIBS technique for the development of quantitative analytical methods in order to determine N, P, K and Ca in new biochar-based fertilizers. (AU)