| Popis: |
Diffuse reflectance spectrometry in combination with chromaticity measurements was used for the determination of trace fluoride ions. The determination method was based on a decrease in the color intensity of the thorium complex of Arsenazo I. Silica gel Silochrom-120 was studied as the substrate. The linearity ranges were determined for chromaticity functions (chromaticity coordinates X, Y, and Z in the X, Y, Z system; lightness L; chromaticity coordinates A and B in the CIELAB system; color saturation S; yellowness G; hue T; whiteness W; and total color difference ΔE); in a homogeneous system, for the sorption on silica gel and in the presence of a surfactant, the linearity ranges are 10–40, 5–20, and 2–15 μg of fluoride per 25 mL of the solution, respectively. The sensitivity of the chromaticity functions as analytical signals and the measurement errors were examined. The procedure was used for the analysis of tap water and toothpaste. |
