XRF - X-ray Fluorescence Spectrometry

X-ray fluorescence spectrometry (XRF) is a non-destructive method of elemental analysis. XRF is based on the principle that each element emits its own characteristic X-ray line spectrum. When an X-ray beam impinges on a target element, orbital electrons are ejected. The resulting vacancies or holes in the inner shells are filled by outer shell electrons. During this process, energy is released in the form of secondary X-rays known as fluorescence. The energy of the emitted X-ray photon is dependent upon the distribution of electrons in the excited atom. Since every element has a unique electron distribution, every element produces... 

LAB 11 Laboratory for analysis of unfiltered water samples, stream sediment and floodplain sediment samples. Ion chromatography (IC) is used for Cf, Br, N03% N02, P043, S042 and ion specific electrode (ISE) for F and Total Organic Carbon (TOC) in water. X-Ray fluorescence spectrometry (XRF) analyses for over 30 elements is used for stream sediment and floodplain sediment samples. To be nominated (suggestion British Geological Survey). 

Inductively coupled plasma atomic emission spectroscopy (ICP-AES) and x-ray fluorescence spectrometry (XRFS) are also used for elemental determination in environmental studies, although they are generally less sensitive than ICP-MS techniques. 

X-ray fluorescence spectrometry (XRF) and instrumental neutron activation analysis (INAA) are commonly used for multi-element analysis of rock, soil, and sediment samples since they do not require chemical dissolution. However, the detection limit for arsenic using XRF is on the order of 5 mg kg and is too high for many environmental purposes. Once dissolved, arsenic can be determined using many of the methods described above... 

These methods include X-ray fluorescence spectrometry (XRF), inductively coupled plasma mass spectrometry (ICPMS), inductively coupled plasma atomic emission spectrometry (ICPAES), and atomic absorption spectrometry (AAS) (Welz and Sperling 1999) the respective detection limits of these methods are summarized in Table 19.1. Also listed are the detection limits for the metallochromic ligand complexes separated by reverse phase-high-per-formance liquid chromatography (RP-HPLC). These ligands include 4-(2-pyridyla-... 

Although no sharp lines can be drawn between nuclear and non-nuclear techniques (see De Goeij and Bode, 1997 for a review), the principle of the nuclear technique says that the analytical information on element and concentration originates from the nucleus and not from the atom. As such, chemical binding, chemical compound or matrix composition has no essential influence on the accuracy of the results (Bode and Wolterbeek, 1990 De Goeij and Bode, 1997). It should be noted here that although techniques such as particle/proton induced X-ray emission (PIXE) and X-ray fluorescence spectrometry (XRF) are basically derived from the behaviour of inner orbital electrons rather than the nucleus itself, they are often counted as a nuclear technique, primarily because inner orbital electrons do not predominate in the characteristics of the atom s chemical behaviour (but see also De Goeij and Bode, 1997 for NMR and Mdssbauer techniques). 

X-ray fluorescence spectrometry (XRF) is currently the most widely used analytical technique in the determination of the major and trace element chemistry of rock samples. It is versatile and can analyse up to 80 elements over a wide range of sensitivities, detecting concentrations from 100 % down to a few parts per million. It is a rapid method and large numbers of precise analyses can be made in a relatively short space of time. The chief limitation is that elements lighter than Na (atomic number 11) cannot be analysed by XRF. Good reviews of the XRF method are given by Norrish and Chappell (1977), Tertian and Claisse (1982), Williams (1987) and Ahmedali (1989). 

For X-ray fluorescence spectrometry (XRF) technique an X-ray excitation source is used and, compared to SEM/EDS, it is more sensitive to higher atomic weight elements and less sensitive to the lower atomic weight elements commonly found in extenders. 

X-ray fluorescence spectrometry (XRF) can be used to determine the content of the basic components of glasses. This multielement analytical technique also does not require dissolving the sample. For a content of 1-100% the precision of the method is not worse than 5%. 

This requirement is met for almost all the important elements by the use of optical emission spectroscopy and X-ray fluorescence spectrometry (XRFS). XRFS is applicable to all elements with an atomic number greater than 12. Using these two techniques, all metals and non-metals down to an atomic number of 15 (phosphorus) can be determined in polymers at tbe required concentrations [1-4]. 

Samsonek J, Puype J, Uype F, YPE F, Vit DD. Rapid determination of certain BFRs in plastics by X-ray fluorescence spectrometry (XRF) and thermal desorption GC-MS (TD-GC-MS) for the RoHS directive. Otganohalogen Compd. 2007 69 2789-92. 

The numbers of papers focusing on the determination of inorganic UV filters is very scarce, perhaps due to the fact that only two compounds, Ti02 and ZnO, are currently used as UV filters. Atomic spectroscopy techniques, such as atomic absorption spectromety (AAS) (Mason, 1980), inductive coupled plasma atomic emission spectrometry (ICP-AES) (Salvador et al, 2000) and X-ray fluorescence spectrometry (XRFS) (Kawauchi et al, 1996) have been used for titanium oxide determination, whereas to our knowledge zinc oxide has only been determined by AAS (Salvador et al, 2000). 

The most commonly used are the atomic spectrometric techniques, especially FAAS, electrothermal atomic absorption spectrometry (ETAAS) and inductive coupled plasma with atomic anision spectrometry (ICP-AES). ICP-MS, X-ray fluorescence spectrometry (XRFS), electroanalytical techniques, UVA IS spectrometry and FL have also been used among others. 

The most common procedures for analyzing cadmium concentrations in blood and urine are inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS). Furthermore, electrochemical methods, neutron activation analysis (NAA) and X-ray fluorescence spectrometry (XRF) can be applied. Several factors influence the choice of the analytical method, e.g. the matrix and the detection limit required. 

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