Search

The study aims to choose the conditions for the direct analysis of different types of natural water samples by total reflection X-Ray fluorescence spectrometry (TXRF). The effect of some factors on TXRF results was studied such as the surface density of dried water residue on the sample carrier, the dilution ratio of high-mineralized samples with ultrapure water and the solution of the detergent Triton X-100, the salt contents, the internal standard concentration, and repeated pipetting of an aliquot of fresh water. The influence of self-absorption phenomena on quantification results was demonstrated by using brine samples. The TXRF results for natural waters of varying salinity (brines, fresh waters, and ground waters) and model solutions are presented. For a number of analytes, the data obtained by TXRF were compared to those obtained by 'wet' chemistry and inductively coupled plasma mass spectrometry. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The design of experiments was used to study sources of errors in the sample preparation and to choose optimal conditions for X-ray fluorescence (XRF) analysis of milk products of varying fat content. The measurements were performed using the conventional wavelength-dispersive XRF (WDXRF) and the total reflection XRF (TXRF) techniques. For WDXRF, the dried milk samples were pelletized, and the mathematical models were constructed, which described the dependence of XRF intensity on the pelletizing pressure, the pellet weight and the milk fat content. The effect of radiation time on the stability of pressed milk powder samples was also estimated. When applying TXRF, the sample preparation involved diluting milk samples with the ultrapure water, adding the internal standard (Ga) and drying of a sample aliquot on a quartz glass sample carrier. The mathematical models were designed, which described the dependence of the sample preparation error on the dilution ratio and sample aliquot pipetted on the carrier. A physical interpretation of the obtained mathematical models was proposed. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]