Wavelength dispersive X-ray fluorescence (WD-XRF) applied to speciation of sulphur in mineral supplement for cattle: Evaluation of the chemical and matrix effects

Publication date: June 2019Source: Microchemical Journal, Volume 147Author(s): Diego Victor Babos, Vinicius Câmara Costa, Edenir Rodrigues Pereira-FilhoAbstractA nondestructive method for speciation of sulphur (S), elemental sulphur and sulphate; and determination of total sulphur in mineral supplements for cattle by wavelength dispersive X-ray fluorescence (WD-XRF) spectrometry is proposed. Using direct solids analysis it was possible to perform S speciation with high analytical frequency, simplicity and precision. The intensities ratio for the different electronic transitions (S Kα1,2, S Kβ and S Kβ′) and principal component analysis (PCA) of the spectra obtained for samples and standards of different inorganic species of S allowed the speciation and quantification of S in mineral supplements for cattle. Matrix effects were minimized using matrix-matching method and univariate and partial least squares (PLS) treatments. The samples containing predominantly sulphate species were used as standards for calibration. For mineral supplement samples that contain predominantly elemental sulphur species, a sample set or S8 diluted in Na2CO3: NaCl (1:1 w/w) were used with standards. No statistically significant difference was observed between method proposed and inductively coupled plasma optical emission spectrometry (ICP OES) reference values at 95% confidence level (Student's t-test, n = 3). The limits of quantification ≤2 g kg−1 S, standard error of calibratio...
Source: Microchemical Journal - Category: Chemistry Source Type: research