Improvement and modification of energy-dispersive X-ray fluorescence method for determination of metal elements in cement leachates-chemometric approach

Abstract

A modification of analytical procedure for energy-dispersive X-ray fluorescence (EDXRF) quantification of ten chemical elements (As, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Zn) in the leachates obtained from cement binders was developed. Twenty-nine testing samples were used in the experiment. All samples were based on Portland cement. Fly ash of different origin, zeolite and bentonite were employed as mineral additives in the cement binders. Distilled water was used as leachate. Validation of the modified EDXRF procedure was conducted in terms of limits of detection and quantification, working range, linearity, selectivity, precision, trueness, and robustness. Traceability of the procedure was established using certified reference materials. Uncertainty of measurement was confirmed via "in-house" laboratory validation approach. The expanded uncertainties for ten analysed elements were obtained for entire working range of EDXRF method. Robustness of the modified EDXRF procedure was assessed by means of chemometric in-house approach. The results obtained by modified X-ray fluorescence method were additionally correlated to those acquired by inductively coupled plasma optical emission spectrometry to confirm that EDXRF can be used as an effective and reliable alternative method for analysis of cement leachates.