Effect of modulation of the particle size distributions in the direct solid analysis by total-reflection X-ray fluorescence

Highlights: • First study of the analytical influence in the DSA-TXRF method of the particle size distribution of solid suspensions. • DSA-TXRF has proven to be a powerful methodology allowing the direct analysis of solid without chemical distortion. • Analytical parameter behaviors of DSA-TXRF method have been evaluated, modeled and fitted. • DSA-TXRF method will allows the design of future ISO protocols for the TXRF analysis of solid matrixes. The main goal of this work was to investigate, in a systematic way, the influence of the controlled modulation of the particle size distribution of a representative solid sample with respect to the more relevant analytical parameters of the Direct Solid Analysis (DSA) by Total-reflection X-Ray Fluorescence (TXRF) quantitative method. In particular, accuracy, uncertainty, linearity and detection limits were correlated with the main parameters of their size distributions for the following elements; Al, Si, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Rb, Sr, Ba and Pb. In all cases strong correlations were finded. The main conclusion of this work can be resumed as follows; the modulation of particles shape to lower average sizes next to a minimization of the width of particle size distributions, produce a strong increment of accuracy, minimization of uncertainties and limit of detections for DSA-TXRF methodology. These achievements allow the future use of the DSA-TXRF analytical methodology for development of ISO norms and standardized protocols for the direct analysis of solids by mean of TXRF.