ISO/TC 201/SC 10 - X-ray Reflectometry (XRR) and X-ray Fluorescence (XRF) Analysis

This document gives guidance on sample preparation, and on qualitative and quantitative determination of elements in particulate matter collected on filtering membranes (PM filter) by energy dispersive X-ray Fluorescence (EDXRF) in different geometrical configurations. This document does not apply to PM filter sampling. This document only applies to the analysis of X-ray emission from filters that are probed using an X-ray beam as the exciting source. X-ray emissions generated by electron microscope are excluded[1]. This document is applicable under a range of contexts including, but not limited to, those highlighted in the introduction. The described method is generally applicable for the determination of elements with atomic number higher than 11 (Na) and having a deposited mass on the filter greater than 10 ng. The elements that can be identified and the detection limits depend on the specific instrumental configuration employed. Various types of filtering membranes (filter) materials can be used, such as glass fibre, quartz fibre, cellulose, nylon, polycarbonate (PC) and polytetrafluoroethylene (PTFE). The entire filter, or portions of various sizes thereof, can be submitted for analysis. NOTE Reference free analysis, based on fundamental parameters is excluded, as the nature of the PM filter samples means that the parameters are not sufficiently well defined.

The document provides the physical principles and specifies instrumental requirements for total reflection X‑ray fluorescence analysis (TXRF) spectrometers. This document specifies general procedures for calibration, method development and verification of TXRF measurements and quality control. The document describes measurements with TXRF conditions having a fixed glancing angle below the critical angle of total reflection and considerably enhanced excitation radiation intensity. Although certain definitions of grazing incidence geometry are shown for clarification, this document is not applicable to measurement setups working under such conditions.

This document specifies a chemical method for technicians working with total reflection X-ray fluorescence (TXRF) instrumentation to perform measurements of water samples, according to good practices, with a defined degree of accuracy and precision. Target users are identified among laboratories performing routine analysis of large numbers of samples, which also conform with ISO/IEC 17025. This document specifies a method to determine the content of elements dissolved in water (e.g. drinking water, surface water and ground water). This document is also applicable for determining elements in waste waters and eluates, taking into account the specific and additionally occurring interferences. This document does not specify sampling, dilution and pre-concentration methods. Elements determined using the method specified in this document can depend on the X-ray source of the instrument. This document does not specify health, safety or commercial aspects. The determinable concentrations depend on the matrix and the interferences encountered. In drinking water and relatively unpolluted waters, the limit of quantification lies between 0,001 mg/l and 0,01 mg/l for most of the elements. The range of concentrations typically lies between 0,001 mg/l and 10 mg/l, depending on the element and predefined requirements. Annex A reports an example of uncertainty calculation. Annex B provides an example report on validation of the method for TXRF analysis of water performed with instrumentation that has Mo as the X-ray source and uses Ga as the internal calibration standard. Limits of quantification of most elements are affected by blank contamination and depend predominantly on the laboratory air-handling facilities available, on the purity of reagents and the cleanliness of labware.

ISO 20289:2018 provides a chemical method for technicians working with Total Reflection X-ray Fluorescence (TXRF) instrumentation to perform measurements of water samples, according to good practices, with a defined degree of accuracy and precision. Target users are identified among laboratories performing routine analysis of large numbers of samples, which also comply with ISO/IEC 17025. ISO 20289:2018 specifies a method to determine the content of elements dissolved in water (for example, drinking water, surface water and ground water). Taking into account the specific and additionally occurring interferences, elements can also be determined in waste waters and eluates. Sampling, dilution and pre-concentration methods are not included in this document. Elements that can be determined with the present method may change according to the X-ray source of the instrument. No health, safety or commercial aspects are considered herewith. The working range depends on the matrix and the interferences encountered. In drinking water and relatively unpolluted waters, the limit of quantification lies between 0,001 mg/l and 0,01 mg/l for most of the elements. The working range typically covers concentrations between 0,001 mg/l and 10 mg/l, depending on the element and predefined requirements. Annex B reports, for example, the complete validation of the method of TXRF analysis of water performed with instrumentation that has Mo as the X-ray source and uses Ga as the internal standard for calibration. Quantification limits of most elements are affected by blank contamination and depend predominantly on the laboratory air-handling facilities available, on the purity of reagents and the cleanliness of labware.