Flame Spectroscopy Analysis B.Pharma and M/Pharma

Flame Spectroscopy Analysis B.Pharma and M/Pharma latest 2021

1. FLAME PHOTOMETRY   BY: AMAN KAPOOR M . PHARM (PHARMACEUTICAL ANALYSIS ) IST SEMESTER

2. CONTENTS • INTRODUCTION • HISTORY • PRINCIPLE • INSTRUMENTATION • SAMPLE INTRODUCTION • BURNERS AND FLAME • MIRRORS • MONOCHROMATORS • DETECTORS • APPLICATIONS • LIMITATIONS

3. INTRODUCTION Flame photometry or Flame Atomic Emission spectroscopy . It is type of emission spectroscopy where Atomic emission is measured using spectrophotometer. Flame Photometer: “An instrument used in Inorganic chemical analysis to determine the concentration of certain metal ions among them sodium, potassium, calcium and lithium . Flame Photometry is based on measurement of intensity of the light emitted when a metal is introduced into flame The wavelength of color tells us what the element is ( qualitative ) The color's intensity tells us how much of the element present ( quantitative ).

4. HISTORY In the later 1800 , scientists such as Kirchhoff, Bunsen, Angstrom, Rowland, Michelson and Balmer studied the composition of the sun based on their emissions at different wavelengths In February of 23rd 1955 Murray Nelson A. filed a patent for invention of Flame Photometry which was granted in year 1958

5. basic principle • Liquid sample containing metal salt solution introduced into a flame • Solvent is vaporized , leaving particles of solid salt • Salt is vaporized into gaseous state • Gaseous molecule dissociate to give neutral atoms • The resulting Neutral atoms are excited by the thermal energy of the flame which are fairly unstable , and hence instantly emit photons and eventually return to the ground state • Photomultiplier tube detectors. Ground state (E0) Excited state (E1) electron Emission

6. Events occur in Flame photometry

7. Bohr’s Equation : If we consider two quantized energy levels e.g., higher as E2 and lower as E1, the radiation given out during the transition from E2 to E1 may be expressed by the following equation E2 – E1 = hv …(a) where , h = Planck’s constant, ν = Frequency of emitted light , now , the frequency v may be defined as follows : ν = c/ λ …(b) where , c = Velocity of light , λ = Wavelength of the absorbed radiation

8. Combining equations (a) and (b) we have : E2 – E1 = hc /λ λ = hc /E2 – E1 …..(c) The expression ( c ) is the Bohr’s equation which enables us to calculate : Wavelength of the emitted radiation which is characteristic of the atoms of the particular element from which it was initially emitted , Wavelength of radiation given out from a flame is indicative of the element(s) that might be present in that flame, and Intensity of radiation may quantify the exact amount of the elements present

9. INSTRUMENTATION SAMPLE DELIEVERY SYSTEM BURNER AND FLAME OR SOURCE MONOCHROMATOR DETECTOR

10. DIAGRAMMATIC REPRESENTATION OF FLAME PHOTOMETRY.

11. SAMPLE DELIVERY OR NEBULIZATION This is the part of sample delivery system in which liquid droplets of comparatively larger size are broken or converted to smaller size. The process of conversion of sample into a mist of very fine droplets through the aid of jets of compressed gas is called nebulization Types of nebulizers: Pneumatic nebulizers Electro-thermal vaporizers Ultrasound nebulizers

12. Overview of the Process

13. 1. pneumatic nebulizers Concentric tube - the liquid sample is sucked through a capillary tube by a high pressure jet of gas flowing around the tip of the capillary (Bennoulli effect). This is also referred to aspiration .. Cross-flow - the jet stream flows at right angles to the capillary tip. The sample is sometimes pumped through the capillary.

14. Cont. Fritted disk - the sample is pumped onto a fritled disk through which the gas jet is flowing. Gives a finer aerosol than the others. Babington - jet is pumped through a small orifice in a sphere on which a thin film of sample flows. This type is less prone to clogging and used for high salt content samples.

15. 2. Electro-thermal vaporizers An electro thermal vaporizer contains an evaporator in a closed chamber through which an inert gas carries the vaporized sample into the atomizer.

16. 3.Ultrasound nebulizers . Ultrasonic Nebulizer - The sample is pumped onto the surface of a vibrating piezoelectric crystal . The resulting mist is denser and more homogeneous than pneumatic nebulizers

17. BURNERS Several kinds of burners are used to convert the fine droplets of sample solution into neutral atom ,which further due to the high heat or temperature of flame are excited hence emit radiation of characteristic wavelength and color . Types of burner used: Mekker or Mecker burner Total consumption burner Premix burner Lundergarph’s burner Shielded burner Nitrous oxide – Acetylene burner 20

18. 1.MECKER OR MEKKER BURNER This was the primitive type of burner used in flame photometry and was used earlier. It generally works with aid of natural gas and oxygen as fuel and oxidant. The temperature so produced in the flame was relatively low, resulting in low excitation energy. Now a days it is not used but it was best suited for alkali metal.

19. 2. TOTAL CONSUMPTION BURNER Due to the high pressure of fuel and oxidant the sample solution is aspirated through capillary and burnt at the tip of burner Hydrogen and oxygen are generally employed as fuel and oxidant . The advantage over other is the entire consumption of sample , It’s disadvantage is the production of non uniform flame and turbulent.

20. 3. PREMIX BURNER In this burner the sample , fuel oxidant are thoroughly mixed before aspiration and reaching to flame . The main advantage of it is the uniformity of flame produced. The main disadvantage is the heavy loss of mix up to 95%.

21. 4. LUNDENGARPH’S BURNER A small l iquid droplets vaporized and move to base of flame in the form of cloud Large droplets condensed at side and then drained off.

22. 6. NITROUS OXIDE-ACETYLENE FLAME These flames were superior to other flames for effectively producing free atoms • E.g.-metals with very reflective oxides such as aluminum and titanium. The drawback of it is: the high temperature reduces its usefulness for the determination of alkali metals as they are easily ionized Intense background emission, which makes the measurement of metal emission very difficult

23. ` list of fuel and oxidant used

24. MIRRORS The radiation emitted by the flame is generally towards all the direction Hence a mirror is place behind the flame to focus the radiation towards the entrance slit of the monochromator. A concave mirror is used as it is front faced reflecting type.

25. MONOCHROMATORS The main of the monochromator is to convert polychromatic light into the monochromatic one The two types of monochromator generally used are as under: 1 . Prism : Quartz material is used for making prism, as quartz is transparent over entire region 2 . Grating : it employs a grating which is essentially a series of parallel straight lines cut into a plane surface

26. DETECTORS

27. Photomultiplier tube The intensity of the light is fairly low, so a photomultiplier tube (PMT) is used to boost the signal intensity A detector (a special type of transducer) is used to generate voltage from the impingement of electrons generated by the photomultiplier tube

28. PHOTOVOLTAIC CELL It has a thin metallic layer coated with silver or gold act as electrode , also has metal base plate which act as another electrode . Two layers are separated by semiconductor layer of selenium , when light radiation falls on selenium layer. This creates potential diff. between the two electrode and cause flow of current .

29. APPLICATIONS QUALITATIVE ANALYSIS : Generally alkali and alkaline earth metal can be estimated by flame photometry As characteristic wavelength is emitted by the element hence detector recognizes that wavelength and atom is detected. Manual method of detection is via flame characteristic color e.g . Na produces yellow color. QUANTITATIVE ANALYSIS : many alkali and alkaline metals amount can be detected by the flame photometry by : 1. E xternal standard 2. Method of standard addition . 3 . Method of internal standard

30. OTHER APPLICATIONS TO ESTIMATE Na , K, Ca , Li IN SERUM, BODY FLUID, CSF AND URINE . Na IN EXTRACELLULAR FLUID AND K INTERACELLULAR FLUID . LITHIUM ESTIMATION IN PSYCHIATRIC THERAPY . IN SOIL ANALYSIS. IN INDUSTRIAL WASTE , GLASS,CEMENT AND PETROLUEM PRODUCTS .

31. Limitations Limited number of elements that can be analyzed . The sample requires to be introduced as solution into fine droplets. Many metallic salts, soil, plant and other compounds are insoluble in common solvents. Hence, they can’t be analyzed by this method. Since sample is volatilized, if small amount of sample is present, it is tough to analyze by this method. As some of it gets wasted by vaporization . Further during solubilisation with solvents, other impurities might mix up with sample and may lead to errors in the spectra observed

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