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

Author(s)

Babos, Diego Victor ^[1] ; Costa, Vinicius Camara ^[1] ; Pereira-Filho, Edenir Rodrigues ^[1]

Affiliation

^[1] Univ Fed Sao Carlos, Dept Chem, Grp Appl Instrumental Anal, POB 676, BR-13560905 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: Microchemical Journal; v. 147, p. 628-634, JUN 2019.
• Web of Science Citations: 2

Abstract

A 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 K alpha(1,2), S K beta and S K beta') 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 S-8 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 calibration <= 3.5 g kg(-1) S, standard error of Cross Validation <= 4.7 g kg(-1) S values obtained for the models proposed. The relative standard error <= 9% were obtained for the proposed method, demonstrating good precision. The method was successfully applied and a good alternative to direct speciation and analysis for determination of S in mineral supplements for cattle. (AU)

• FAPESP's process: 16/01513-0 - Laser-Induced Breakdown Spectroscopy (LIBS) application in the analyses of electronic waste (printed circuit boards and polymers), food and difficult preparation liquid samples
• Grantee: Edenir Rodrigues Pereira Filho
• Support Opportunities: Regular Research Grants