FLAME PHOTOMETER

An instrument used in inorganic chemical analysis to determine the concentration of certain metal ions among them sodium, potassium, calcium and lithium

1. FLAME PHOTOMETER Presented By: Zainab Arshad BS Hons, Environmental Sciences University Of Gujrat, Pakistan 1

2. Contents: Introduction Based on Principle Parts of Flame Photometer Structure of flame Applications Advantages Disadvantages 2

3. Introduction: Flame Photometry or Flame Atomic Emission Spectrometry is a branch of spectroscopy in which the species examined in the spectrometer are in the form of atoms. Flame Photometer: “An instrument used in inorganic chemical analysis to determine the concentration of certain metal ions among them sodium, potassium, calcium and lithium.” 3

4. Based on: intensity of the light The wavelength of color (qualitative). The color's intensity tells (quantitative). 4

5. Principle Liquid sample contaning metal salt solution introduced into a flame: Solvent is vaporised , leaving particles of solid salt Salt is vaporised into gaseous state Gaseous molecule dissociate to give neutral atoms 5

6. Parts of a Flame Photometer Source of Flame Nebulizer and Mixing Chamber Optical System (Optical Filter): Photo Detector 6

7. Parts of a Flame Photometer Source of flame A burner that provides flame and can be maintained in a constant form and at a constant temperature. 7

8. Structure of Flame: As seen in the figure, the flame may be divided into the following regions or zones. Preheating zones Primary reaction zone or inner zone Internal zone Secondary reaction zone 8

9. Structure of Flame: preheating zone: In this combustion mixture is heated to the ignition temperature by thermal conduction from the primary reaction zone. primary reaction zone: This zone is about 0.1 mm thick at atmospheric pressure. There is no thermodynamic equilibrium in this zone and the concentration of ions and free radicals is very high. This region is not used for flame photometry. 9

10. Structure of Flame: Interconial zone: It can extend up to considerable height. The maximum temperature is achieved just above the tip of the inner zone. This zone is used for flame photometry. Secondary reaction zone: In this zone, the products of the combustion processes are burnt to stable molecular species by the surrounding air. 10

11. Requirements of flame: It should have proper temperature Temperature should remain constant throughout the operation There should not be any fluctuation during burning. 11

12. Functions of flame: To convert the analyst of the liquid sample into vapor state To decompose the analyst into atoms and simple molecules To excite the formed atoms/free atoms/simple molecules to emit radiant energy. 12

13. Parts of a Flame Photometer Nebulizer and Mixing Chamber: Helps to transport the homogeneous solution of the substance into the flame at a steady rate. 13

14. Parts of a Flame Photometer Optical System (Optical Filter): The optical system comprises three parts: convex mirror, lens and filter. The convex mirror helps to transmit light emitted from the atoms and focus the emissions to the lens. The convex lens help to focus the light on a point called slit. The reflections from the mirror pass through the slit and reach the filters. 14

15. Parts of a Flame Photometer Photo Detector: Detect the emitted light and measure the intensity of radiation emitted by the flame. That is, the emitted radiation is converted to an electrical signal with the help of photo detector. The produced electrical signals are directly proportional to the intensity of light. 15

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17. Mechanism: The solvent is first evaporated leaving fine divided solid particles. This solid particle move towards the flame, where the gaseous atoms and ions are produced. The ions absorb the energy from the flame and excited to high energy levels. When the atoms return to the ground state radiation of the characteristic element is emitted. The intensity of emitted light is related to the concentration of the element. 17

18. Applications: It is used To determination of alkali and alkaline earth metals. In Potash and fertilizer industry Soil and environmental analysis For Drinking water treatment In Glass industry For Clinical applications 18

19. Advantages: It have many advantages like: Fast and sensitive Typical precision and high accuracy Suitable for many metallic elements Inexpensive Quite quick, convenient, and selective and sensitive to even parts per million (ppm) to parts per billion (ppb) range. 19

20. Disadvantages: It have some disadvantages. which is: standard solution with known molarities is required difficult to obtain the accurate results of ions with higher concentration information about the molecular structure cannot be determined Elements of non-radiating nature can’t be detected careful and frequent calibration needed 20

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