Electron Spectroscopy for Chemical Analysis (ESCA) is a method for identification of the elemental composition of the surface of a sample (20-50Å). The method uses a monochromatic X-ray beam to cause emission of core electrons. The kinetic energy of the emitted electrons is equal to the incident X-ray energy less the binding energy of the electron and the work function of the instrument. The observed kinetic energy of the electrons is then related to binding energy allowing element identification. The binding energy is also related to the chemical environment of the atom and thus can be used to provide information about such features as oxidation state.
EDAX or XRD
Energy Dispersive X-ray Spectroscopy (EDX or EDAX) is a tool for elemental analysis coupled with Scanning Electron Microscopy (SEM). This method can be used to form elemental maps which are particularly useful for identifying the elemental composition of contaminant particles within a larger sample. This technique is based upon ejection of characteristic X-rays following bombardment of the sample with an electron beam. The bean causes ejection of electrons from the atoms of the sample. X-rays are emitted by the sample as a part of the process of returning to the ground state when the electron vacancies are filled.
Inductively Coupled Plasma Mass Spectroscopy (ICP-MS)
Dependent on the element being quantitated and suspected concentration – This technique combines a highly sensitive mass spectrometric detector (ppm to low ppb range) with an inductively coupled plasma source. The sample is burned and the resulting components are identified based on their characteristic ions. Sample digestion is required prior to analysis and losses of the sample component of interest can result. This technique is applicable for a broad range of metals.
Neutron Activation Analysis (NAA)
NAA is one of the most sensitive analytical techniques used for multi-element analysis available today. The NAA procedure is capable of providing both quantitative and qualitative results for individual elements, with sensitivities that are superior to those possible by any other analytical technique. This technique can be used to analyze 75 individual elements (including certain organic elements) at trace levels.
Proton Induced X-ray Emission (PIXE)
This is a non-destructive technique in which the simultaneous determination of the elemental composition from Sodium through Uranium can be determined. Samples which are appropriate for PIXE analysis include solids, liquids, thin films, and aerosol filter samples. PIXE is sensitive to the elemental composition of the sample and not the arrangement of the atoms. Samples are analyzed by bombardment with a proton beam. The protons interact with the electrons in the atoms of the sample forming inner shell vacancies. The energy of the X-rays emitted when the vacancies are refilled are characteristic of the element from which they originate. The relative intensities of the X-rays then serve as a means to quantitate the individual elements.