10.22184/2227-572X.2026.16.4.296.301
The paper presents the evaluation of instrumental conditions (excitation quantum energy) and the analytical range for silver determination in complex geological matrices using synchrotron radiation X-ray fluorescence analysis (SR-XRF) without chemical sample preparation by reducing the detection limit to the lower bound of ore-grade concentrations. The study investigated certified reference materials (CRMs) of black shales (SCHS‑1 and SLg‑1), loose sediments (SGHM‑3 and SGHM‑4), and copper-­nickel sulfide ore (VT‑1). Silver determination was performed on pressed powder pellets of the CRMs with an average mass of 22,9±0,7 mg and a density of 0,4 g/cm3 using both external calibration and direct external standard methods. SR-XRF analysis of the samples at an excitation energy of 30 keV yielded fluorescence spectra for the specified CRMs, exhibiting peaks corresponding to the Kα1,2 and Kβ1–3 lines of Ag at 22,16; 21,99; 24,94; 25,46 and 24,91 keV, respectively, with the latter detected at concentrations of 34 mg/kg. The limit of detection for silver was 0,5 and 1,7 mg/kg for the direct external standard method and 1,4 mg/kg for the external calibration method. While both methods offer comparable accuracy for silver determination in silicate and anthropogenic matrices, the calibration method is more versatile, robust against matrix effects, and comprehensively accounts for instrumental errors as well as instrumental and background fluctuations.