Elemental Analysis of Environmental Samples by Total Reflection X‐Ray Fluorescence: a Review

A review of total reflection x-ray fluorescence (TXRF) as an effective excitation mode for energy-dispersive x-ray spectral analysis is presented. The instrumental conditions of excitation under grazing incidence (ψ < 0.1°) are emphasized and the analytical features of powerful detection and simple and reliable quantification are characterized. The applicability of TXRF to environmental analyses is illustrated by some typical examples. The analysis of pure water samples leads to detection limits at the ppt (ng/l) level. A special matrix separation is only needed for river, sea and waste waters. The analysis of air dust is directly possible with a sampling volume of 1 m 3 and a sampling time of 1 h. Organ tissue can be analysed down to the lower ppm range after freeze-cutting of μm thick sections. Plant material has to be pulverized and digested prior to analysis, e.g. with nitric acid In combination with a chromatographic separation, speciation is made possible for small 0.5 ml fractions, e.g. for vegetable foodstuffs. For all these applications a multi-element determination can be carried out, for about 20-25 elements simultaneously. Simple and reliable quantification is effected by internal standardization. The reliability of the method has been proved by intercomparison tests. Second-generation instruments that are compact and user-friendly are now commercially available.