Instruments for Optical Spectrometry

Chapter 24 Introduction to Spectrochemical Methods 710 Chapter 25 Instruments for Optical Spectrometry 744... 

As in the sources used in optical atomic spectrometry a considerable ionization takes place, they are also of use as ion sources for mass spectrometry. Although an overall treatment of instrumentation for mass spectrometry is given in other textbooks [68], the most common types of mass spectrometers will be briefly outlined here. In particular, the new types of elemental mass spectrometry sources have to be considered, namely the glow discharges and the inductively and eventually the microwave plasmas. In contrast with classical high voltage spark mass spectrometry (for a review see Ref. [69]) or thermionic mass spectrometry (see e.g. Ref. [70]), the plasma sources mentioned are operated at a pressure which is considerably... 

Instrumentation for inductively coupled plasma-optical emission spectrometry. 

Figure 1.2 shows the basic instrumentation for atomic mass spectrometry. The component where the ions are produced and sampled from is the ion source. Unlike optical spectroscopy, the ion sampling interface is in intimate contact with the ion source because the ions must be extracted into the vacuum conditions of the mass spectrometer. The ions are separated with respect to mass by the mass analyser, usually a quadrupole, and literally counted by means of an electron multiplier detector. The ion signal for each... 

In the above section the photodevices that can be employed to reach the appropriate reactant state were outlined. In the remainder of the chapter, the devices and instruments for monitoring the subsequent change and determining the rate characteristics will be discussed. By far the most frequently employed diagnostic techniques are optical absorption and emission spectrometry other less-used methodologies include light-scattering spectrometry, and the electron-spin-based spectroscopies, such as EPR, ENDOR, and CIDNP. These last three are not addressed in this review. 

The WITec alpha300 R confocal Raman microscope can be upgraded to perform atomic force microscopy (AFM), tip-enhanced Raman spectrometry and near-field scanning optical microscopy, and is arguably the most versatile instrument for Raman microspectroscopy available today. 

Instrumentation for X-ray spectrometry requires a source, a wavelength (or energy) selector, a detector, and beam conditioners. Component parts of the instrument are similar for XRF, XRD, and the other fields, but the optical system varies for each one. One major point to note is that some systems have the source located above the sample (the sample is faceup to the X-ray beam) other systems have the source located below the sample, with the sample facedown to the beam. There are advantages and disadvantages to both designs, as will be discussed later in this chapter. 

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