Flame spectroscopy

3 Applications of Flame Emission Spectroscopy in Pharmaceutical analysis 

1 Assay of Sodium, Potassium, and Calcium in blood serum and water 

2 Assay of Barium, Potassium and Sodium in Cacium Acetate 

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-I The liquid sample containing a suitable compound of the metal (M+ A ) is aspirated into a flame, thereby converting it into its vapours or liquid droplets, 

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The production of ground-state gaseous atoms which is the basis of flame spectroscopy may be inhibited by two main forms of chemical interference (a) by stable compound formation, or (b) by ionisation. 

The simplest form of emission spectroscopy is called flame spectroscopy. Flame spectroscopy can be used to identify some common elements. No fancy equipment is needed. The best way to do flame spectroscopy is to use a platinum loop. This piece of standard laboratory gear consists of a fine, 2-inch (5.1-cm) platinum wire twisted into a loop and embedded in a 4-inch (10.2-cm) glass rod. The only other lab equipment needed is a Bunsen burner or its equivalent. 

Alkemade C, Th J, Hermann R (1979) Fundamentals of analytical flame spectroscopy. Adam Hilger, Bristol... 

The DART large programme at ESO made v ei and [Fe/H] measurements from FLAMES spectroscopy of 401 red giant branch (RGB) stars in the Sculptor (Scl) dSph [6]. The relatively high signal/noise, S/N ( 10-20 per pixel) resulted in both accurate metallicities ( 0.1 dex from internal errors) and radial velocities ( 2 km/s). This is the first time that a large sample of accurate velocities and metallicities have been measured in a dwarf galaxy. 

Discuss the following theoretical aspects of flame spectroscopy ... 

The various points of merit of atomic absorption spectroscopy over flame spectroscopy are enumerated below ... 

R. Mavrodineanu and H. Boiteux, Flame Spectroscopy , John Wiley, New York 1965. 

Operating Principles — There are many similarities between ICP-AES and the combustion flame spectroscopy techniques of flame atomic emission (FAE) and flame atomic absorption (FAA). In fact, the source of the ICP-AES has been referred to by Fassel as an electric flame. The final prepared analytical sample is presented in liquid form for analysis except for unique situations. The liquid sample is drawn (or... 

Fassel, V. A. Electrical Flame Spectroscopy in Proceedings XVI Colloquium Spectroscopicion Internationale, Adam Hilger, London, 1971, pp. 63-93. 

Analysis. The colorimetric method for In is capable of a detection limit of 20 ppb. Indium or an In compound in the flame gives an indigo blue color (451.1 nm). This photon line allows for the spectrophotometric determination ofinby AAS (atomic absorption flame spectroscopy). The method is sensitive to about 300 ppb. With ETAAS, this limit drops to 10 ppb, as it does with ICPAES. ICPMS drops the limit to 0.01 ppb. Alizarin detects In, as well as Al, but the reaction with Al can be masked by addition of F to a spot test. The limit of detection is about 1 ppm. 

Alkemade, C.T.J. and Herrmann, R. (1979) Fundamentals of Analytical Flame Spectroscopy, Hilger, Bristol. 

In flame spectroscopy, the residence time of analyte in the optical path is < 1 s as it rises through the flame. A graphite furnace confines the atomized sample in the optical path for several seconds, thereby affording higher sensitivity. Whereas 1—2 mL is the minimum volume of solution necessary for flame analysis, as little as 1 pL is adequate for a furnace. Precision is rarely better than 5-10% with manual sample injection, but automated injection improves reproducibility to —1%. 

Commission on spectrochemical and other optical procedures for analysis, nomenclature, symbols, units and their usage in spectrochemical analysis. I. General atomic emission spectroscopy. II. Data interpretation. III. Analytical flame spectroscopy and associated procedures, Spectrochim. Acta, 33B, 219, 1978. 

Parsons, M.L., Smith, B.W., and Bentley, G.E., Handbook of Flame Spectroscopy, Plenum Press, New York, 1975. 

Wittenberg, G.K., Haun, D.V., and Parsons, M.L., The use of free-energy minimization for calculating beta factors and equilibrium compositions in flame spectroscopy, Appl. Spectrosc., 33, 626, 1979. 

Alkemade, C. T. J. Herrmann, R. Fundamental of Analytical Flame Spectroscopy. Halsted Press New York, 1979. 

As an element, K is eighth most abundant in the Earth s crust, whereas itis but 19th in the universe. This is because its oxide, K20, is so easily made and so tightly bound into rocks that K remained in the crust when many metals sank to the molten coreofEarth. In flame-spectroscopy, K can be recognized by its spectral lines, a doublet in the far red with wavelengths 7697 and 7663 A and a blue line at 4044 A. Together they produce a violet hue. 

Potassium has been studied in stellar optical spectra. The famous red K lines at 7663 and 7697 A have been used. This pair of lines played a role in the history of K flame spectroscopy. As nucleosynthesis progressed the galactic K/H abundance ratio innewly born observed stars increased from 10 3 of solar in some early stars to a bitin excess of solar K/H today. If compared instead to Mg, the ratio K/Mg remains near the solar ratio in stars of all metallicities. This is understood as the coproduction of K and Mg in massive Type II supernovae. 

R. Mavrodineanu in R. Mavrodineanu (Ed.), Analytical Flame Spectroscopy — Selected Topics, Springer-Verlag, New York, 1970, Ch. 13. 

Varian Techtron, Analytical Methods for Flame Spectroscopy, Springvale, Australia, 1972. 

Fig 40.4 (a) An approximately log-transformed distribution particle size of droplets In flame spectroscopy. (b)The results in (a) plotted against the logarithm of particle size. 

When new analytical tools become available, more often than not considerations of responsibility to the patient, practicality, and economy will keep the clinical chemist from accepting such newly developed techniques without careful deliberation. It appears that presently atomic abso tion spectroscopy is slowly finding entrance into medical research and service laboratories, and there is reason to expect that this technique will find wider use and greater application than emission flame spectroscopy. Virtually all metals, with very few exceptions, can be determined by atomic absorption spectroscopy. It is anticipated that this technique not only will replace currently used analytical methods for metals, but will also make feasible the routine determination of elements now impractical by conventional means. Furthermore, the operational stability of available instruments and the simplicity of actual performance of measiurements make this technique well suited for automation, by addition of an automatic sample feed and automatic recording. 

Following the work of Lundegardh in the twenties, emission flame spectroscopy became established as an analytical tool in almost every branch of science. Although hollow cathode tubes were first studied by Paschen (P2) in 1916, and although atomic absorption spectroscopy had found occasional application, notably in the mercury vapor detector W20), it remained for Walsh (W2) in Australia in 1955 to recognize the essential advantages inherent in absorption over emission methods and revive general interest in this technique. Shortly thereafter but apparently independently, Alkemade and Milatz (A2, A3) in Holland devised instruments and applied atomic absorption spectroscopy in their laboratory. Walsh and his co-workers have since contributed a remarkable volume of work on instrumentation and application, and patents are held by Walsh on his method in Australia, Europe, and America. 

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