Flame emission spectroscopy FES

This chapter describes the basic principles and practice of emission spectroscopy using non-flame atomisation sources. [Details on flame emission spectroscopy (FES) are to be found in Chapter 21.] The first part of this chapter (Sections 20.2-20.6) is devoted to emission spectroscopy based on electric arc and electric spark sources and is often described as emission spectrography. The final part of the chapter (Sections 20.7-20.11) deals with emission spectroscopy based on plasma sources. 

Metallic salts (or metallic compounds) after dissolution in appropriate solvents when introduced into a flame (for instance acetylene burning in oxygen at 3200°C), turns into its vapours that essentially contain mostly the atoms of the metal. Quite a few such gaseous metal atoms are usually raised to a particular high energy level that enables them to allow the emission of radiation characteristics features of the metal for example-the characteristic flame colourations of metals frequently encountered in simple organic compounds such as Na-yellow, Ca-brick-red Ba-apple-green. This forms the fundamental basis of initially called Flame Photometry, but more recently known as Flame Emission Spectroscopy (FES). 

Step-V The thermal excitation of some atoms into their respective higher energy levels will lead ultimately to a condition whereby they radiate energy (flame emission) measured by Flame Emission Spectroscopy (FES), and... 

The underlying principle of Flame Emission Spectroscopy (FES) may be explained when a liquid sample containing a metallic salt solution under investigation is introduced into a flame, the following steps normally take place in quick succession, namely ... 

Therefore, the fraction of atoms excited critically depends on the temperature of the flame thereby emphasizing the vital importance of controlling the temperature in Flame Emission Spectroscopy (FES). 

What are the two types of Flame Photometers commonly used in Flame Emission Spectroscopy (FES) Describe them individually with a neat layout and explain their modus operandi. 

In flame emission spectroscopy (FES), the radiation intensity emitted by a small fraction of the atoms that have passed into the excited state by the elevated temperature is measured. 

Undoubtedly, while the direct method is more relevant, because the analyte activity in water plasma is actually measured, the reporting on blood sodium, potassium and chloride in terms of concentration in plasma is preferred by medical professionals, whatever method of measurement is used. This is justified by the fact that before ISEs had been invented, sodium, potassium and chloride were all determined by indirect methods, with flame emission spectroscopy (FES) for Na+ and K+, and coulometry for Cl. ... 

Atomic absorption spectroscopy (AAS) and flame emission spectroscopy (FES), also called flame photometry, are two analytical measurement methods relying on the spectroscopic processes of excitation and emission. Methods of quantitative analysis only, they are used to measure of around seventy elements (metal or non-metal). Many models of these instruments allow measurements to be conducted by these two techniques although their functioning principles are different. There exists a broad range of applications, as concentrations to the gtg/L (ppb) level can be accessed for certain elements. 

Finally, in Table Ic [17] a comparison is made of detection limits for carbon furnace atomic emission spectroscopy (CFAES), flame emission spectroscopy (FES), and CFAAS. Note that sensitivities are used as pseudo-detection limits for CFAAS. These are not really sensitivities as defined by lUPAC [18], but are characteristic concentrations, since they represent a concentration equivalent to an absorbance of 0.0044. Furthermore, noise... 

Flame emission spectroscopy (FES) is a good choice if we have very small amounts of the alkali metals. 

Experimentally determined detection limits provide the analyst with realistic numerical data for comparing capabilities of several techniques for determining trace elements and for estimating the lowest concentrations determinable under specific circumstances. The analyst may draw these data from a variety of compilations (Fassel and Golightly, 1967 Slavin, 1968 Kniseley et al., 1970 Christian and Feldman, 1970 and 1971 and others cited earlier). Published comparisons may be viewed as reflecting the present state of the art . A side-by-side comparison of flame emission spectroscopy (FES), atomic absorp-... 

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