Open AccessSolid‐phase cadmium speciation in soil using L 3 ‐edge XANES spectroscopy with partial least‐squares regression
Author(s) -
Siebers Nina,
Kruse Jens,
Eckhardt KaiUwe,
Hu Yongfeng,
Leinweber Peter
Publication year - 2012
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049512021371
Subject(s) - partial least squares regression , xanes , genetic algorithm , cadmium , chemistry , analytical chemistry (journal) , ternary operation , phase (matter) , spectroscopy , mathematics , environmental chemistry , physics , statistics , computer science , organic chemistry , quantum mechanics , evolutionary biology , biology , programming language
Cadmium (Cd) has a high toxicity and resolving its speciation in soil is challenging but essential for estimating the environmental risk. In this study partial least‐square (PLS) regression was tested for its capability to deconvolute Cd L 3 ‐edge X‐ray absorption near‐edge structure (XANES) spectra of multi‐compound mixtures. For this, a library of Cd reference compound spectra and a spectrum of a soil sample were acquired. A good coefficient of determination ( R 2 ) of Cd compounds in mixtures was obtained for the PLS model using binary and ternary mixtures of various Cd reference compounds proving the validity of this approach. In order to describe complex systems like soil, multi‐compound mixtures of a variety of Cd compounds must be included in the PLS model. The obtained PLS regression model was then applied to a highly Cd‐contaminated soil revealing Cd 3 (PO 4 ) 2 (36.1%), Cd(NO 3 ) 2 ·4H 2 O (24.5%), Cd(OH) 2 (21.7%), CdCO 3 (17.1%) and CdCl 2 (0.4%). These preliminary results proved that PLS regression is a promising approach for a direct determination of Cd speciation in the solid phase of a soil sample.