Flame Emission Spectroscopy (FES) Instrumentation

Flame Emission Spectroscopy
CONTENT:
introduction, Principal, Instrumentation.

1. Centre for Health and Applied Science (CHAS), Ganpat University , Ganpat Vidhyanagar, Mahesana-Gozaria Highway, Kerva -384012 Gujarat, India. G UIDED BY :- Dr. Satish A. Patel Associate Professor M.Pharm, Ph.D . p repared BY :- Ankitkumar S. Vasoya Enroll No. - 19304591015 Semester - 1 Flame Emission Spectroscopy 1 A Seminar On Dec 2019 M.Sc. Pharma Analysis

2. Introductions General Principle Instrumentation Burner Mirror Slit System Monochromator Filter Detector Reference 2 Overview

3. Flame photometry is a branch of spectroscopy. More accurately called Flame Atomic Emission Spectroscopy (FES). Flame photometry is based on the measurement of intensity of the light emitted when a metal is introduce into a flame to identify the element . A flame photometry is used to determine the concentration certain metal ions. Particularly – Alkali metals , Alkali earth metals . 3 Introduction

4. 4 General Principle When a solution of metallic salt sprayed as fine droplets into a flame . The heat energy (thermal energy) of the flame the solvent in the droplets dry, leaving a fine residue . This residue convert into neutral atoms . Due to thermal energy of the flame the neutral atoms are converted to exited status atoms. As the exited state atoms is not stable and the exited state atoms return to ground state with the emission of radiation is in specific wavelength. The wavelength of the radiation emitted is specific for every element and is used to identify the element ( Qualitative Analysis). The intensity of emitted radiation depends upon the concentration of the elements (Quantitative Analysis).

5. The basic components are Light Source Mirror Monochromator Slit system Detector Read out device (ROD). 5 Instrumentation Fuel Oxidant Sample

6. The flame used in the flame photometry must possess the following Functions: The ability to evaporate the liquid droplets from the sample solution, resulting in the formation of solid residue. The solid residue resulting in the formation of atoms . Must have the capability to excite the atoms. Cause them to emit radiant energy. These processes is controlled by several factors which are summarised as follows: Type of fuel and oxidant & fuel-oxidant ratio . Type of solvent Amount of solvent Type of burner 6 BURNER

7. Total Consumption Burner F uel and oxidant are hydrogen and oxygen . L iquid sample is drawn into the flame from the side tubing hydrogen and oxygen are entering. B oth are burning at the top of the burner to produce the flame. As soon as the liquid sample is drawn into the base of flame, the oxygen aspirates sample solution leaving a solid residue. Atomisation and excitation of the sample then follow . 7 The name “ Total Consumption Burner ” is used because all the sample that enters the capillary tube will enter the flame regardless of droplets size. The flame is noisy and turbulent . I t can be adjusted by proper control of fuel-to-oxidant ratio. Capillary Tip Burner Tip Fuel Intel Oxygen Intel Capillary Total Consumption Butner

8. In this energy type of burner, aspirated sample, fuel and oxidant are thoroughly mixed before reaching the burner opening and then entering the flame. 8 Premix Burner In this burner the gases move in non-turbulent fashion, in laminar flow . Fuel Oxidant Aspirator air Sample Drain Flame Mixing baffles

9. 9 Only small portion about 5% of the sample in the form of small droplets reaches the flame and is easily decomposed. An efficient atomization of the sample in the side of the spray chamber and are drained off. 95% of the sample be wasted these by resulting in a loss of sensitive. However, this lost must be balanced against the loss of larger droplets. The flame produced by premix burner is non turbulent, noiseless and stable.

10. The flame is emits the radiation in all direction in the space. Much of the radius is lost and loss of signal results. In order to maximize the amount of radiation used in the analysis. A mirror is located behind the burner to reflect the radiation back to the entrance late of the monochromator. The mirror is concave and curves as wide a solid angle from the flame as possible. To get the best results, hottest and studies part of the flame. This helps reduce flame flicker . 10 Mirror Concave Mirror

11. 11 Slits The exit side slit is placed after a monochromator and allows only a selected wavelength range to pass through the detector. It is necessary if emission line from other components in the flame have a wavelength similar to those of the emission line of the elements. Translate must prevent search interfering line from reaching the detector. With the best equipment entrance and exit delete are used before and after the dispersion element. The entrance slit cut out most of the radiation from the surrounding area and allows only the flames radiation and mirror reflected radiation of the flame to enter the optical system .

12. 12 Monochromator In simple flame photometer, the monochromator is prism but in expensive model the grating used as monochromator. Quartz is the material most commonly used for making prism even through its dispersive power is less than the glass. The grating monochromator employees of grating which is essentially a series of parallel straight line got into a plane surface.

13. 13 Filter In some element , the emission spectrum contains of few line . In such cases wide wavelength range will be allowed to enter the detector without causing any serious error. In such a situation and optical filter may be used in place of the slit and monochromator system . The filter is made from such a material which is transparent over narrow spectral range.

14. 14 Detectors Device which convert energy into electrical signal that are displayed on readout devices . Radiation coming from the optical system is allowed to fall on the detector which measure the intensity of radiation falling on it. The detector should be sensitive to radiation of all wavelength that may be examined .

15. 15 Phototube Consists of a evacuated glass tube with a photocathode and a collector anode . The surface of photocathode is coated with a layer of elements like C aesium , Silver Oxide or mixture of them . When radiant energy falls on photosensitive cathode, electrons are emitted which are attracted to anode causing current to flow .

16. 16 Photomultiplier Tube The principle employed in this detectors is that, multiplication of photoelectrons by secondary emission of electrons. In a vacuum tube, a primary photo cathode is fixed which receives radiation from the sample . Some eight to ten dynodes are fixed each with increasing potential of 75-100 V higher than preceding one. Near the last dynode is fixed an anode or electron collector electrode. Photo-multiplier is extremely sensitive to light and is best suited where weaker / low radiation is received .

17. 17 References Gurdeep R. Chatwal, Sham K. Anand. Flame Photometry and Flame Infrared Emission (FIRE ). Instrument Method of Chemical Analysis, 5 th edition, Himalaya Publishing House: 2018, Pg. 2.367, 2.370-2.375. Dr. S. Ravi Sankar . Flame Photometry. Text bool of Pharmaceutical Analysis, 4 th Edition, Rx Publication, Pg. 26-1, 26-13. Dr. G Vidya Sagar. Flame Photometry. Text book of Instrument Method of Drug Analysis, PharmaMed Press, – P=275 https://lab-training.com/2017/09/26/understanding-of-light-dispersing-elements-in-a-spectrometer/

18. 18 Thank You