TY  - JOUR
A1  - Rühlmann, Madlen
A1  - Büchele, Dominique
A1  - Ostermann, Markus
A1  - Bald, Ilko
A1  - Schmid, Thomas
T1  - Challenges in the quantification of nutrients in soils using laser-induced breakdown spectroscopy
BT  - a case study with calcium
JF  - Spectrochimica Acta Part B: Atomic Spectroscopy
N2  - The quantification of the elemental content in soils with laser-induced breakdown spectroscopy (LIBS) is challenging because of matrix effects strongly influencing the plasma formation and LIBS signal. Furthermore, soil heterogeneity at the micrometre scale can affect the accuracy of analytical results. In this paper, the impact of univariate and multivariate data evaluation approaches on the quantification of nutrients in soil is discussed. Exemplarily, results for calcium are shown, which reflect trends also observed for other elements like magnesium, silicon and iron. For the calibration models, 16 certified reference soils were used. With univariate and multivariate approaches, the calcium mass fractions in 60 soils from different testing grounds in Germany were calculated. The latter approach consisted of a principal component analysis (PCA) of adequately pre-treated data for classification and identification of outliers, followed by partial least squares regression (PLSR) for quantification. For validation, the soils were also characterised with inductively coupled plasma optical emission spectroscopy (ICP OES) and X-ray fluorescence (XRF) analysis. Deviations between the LIBS quantification results and the reference analytical results are discussed.
KW  - Laser-induced breakdown spectroscopy (LIBS)
KW  - Soil
KW  - Multivariate data analysis
KW  - Principal component analysis (PCA)
KW  - Partial least squares regression (PLSR)
Y1  - 2018
U6  - https://doi.org/10.1016/j.sab.2018.05.003
SN  - 0584-8547
VL  - 146
SP  - 115
EP  - 121
PB  - Elsevier
CY  - Oxford
ER  -