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Owing to advancements in XRF spectrometry, EDXRF systems are used in combination with scanning electron microscopy () to determine elemental constituents at small scales. Importantly, XRF is used with synchrotron radiation sources (SRXRF) which is very similar to μ‐XRF that covers numerous applications.

There exist many analytical techniques such as XRF, μ‐XRF, SRXRF, total reflection X‐ray spectroscopy (TXRF), atomic absorption spectrometry (AAS), laser‐induced breakdown spectroscopy (LIBS), laser ablation inductively coupled plasma mass spectroscopy (LA‐ICP‐MS), inductively coupled plasma optical emission spectrometry (ICP‐OES), time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS), PIXE, etc. which are currently being used for elemental analysis of materials, including biological samples. Some important parameters that distinguish the analytical capabilities of the techniques such as elemental range, imaging possibility, depth resolution, and instrumental effort are summarized in Table 1.1 [3,8–11].

All the techniques have their own advantages and different analytical capabilities that can be used to analyze different kinds of materials. Also, the instrumental efforts of these techniques are also different and thus, some techniques require more or less effort on the part of the operator. PIXE and synchrotron radiation‐XRF require high instrumental effort [3, 8, 9]. Additionally, complex sample handling is necessary in ultrahigh vacuum for Auger electron spectrometry, transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), and secondary ion mass spectrometry (SIMS) [3, 8]. On the other hand, a complex laser interaction with the samples occurs in LA‐ICP‐MS. However, a few methods with a restricted spatial resolution, such as conventional XRF or atomic emission spectroscopy (AES), are also available and are often used for elemental analysis in comparison to above techniques.

The methods discussed above produce similar information about the sample compositions and in most cases they provide complementary information. The utility of these techniques depends on their analytical performance and availability particularly their costs.

Figure 1.1 shows a concise visual reference for comparing analytical techniques used for materials characterization, elemental analysis, evaluation surface analysis, and purity surveys etc. in terms of their detection limits and analytical resolutions.