Flame emission spectroscopy

flame emission spectroscopy
1.definition about flame emission spectroscopy
2.theories about flame emission spectroscopy
3.principle of FES
4.instrumentation
5.pharmaceutical application

1. FLAME PHOTOMETRY

2. CONTENT 1.DEFINITION 2. THEORIES 3.PRINCIPLE 4. INSTRUMENTATION 5.PHARMACEUTICAL APPLICATION

3. FLAME PHOTOMETRY DEFINITION : Flame photometry is also called as flame emission spectroscopy , since Neutral atoms are involved in the emission of radiation at specific wave length when introduced into the flame. INTRODUCTION : Flame photometery has been the proven standard method for the analysis of sodium or potassium for the last 70 years . The accurate and reproducible analysis of these elements are crucial in the clinical and many industrial fields

4. PRINCIPLE OF FLAME PHOTOMETRY Liquid sample (metallic salt solution) Formation of droplet Fine residue Formation of Neutral atoms Excitation of atom by thermal energy Emission of radiation of specific wavelength λ & intensity of emitted radiation measured

5. WAVE LENGTH EQUATION A. The wave length of radiation emitted is different for different elements. EXAMPLE: 1.sodium emits yellow at 589nm 2.potassium emits orange at 767nm 3.calcium emits brick red colour at 422,554 and 626nm B. The wave length of the radiation emitted is given by the following equation Wave Length of light emitted ( λ ) = hc /E2-E1 h = plank’s constant C = velocity of light E2,E1 = energy levels of excited and ground state respectively

6. THEORIES OF FLAME EMISSON SPECTROSCOPY The following equation are applicable to the flame emission spectroscopy 1. Bohrs Equation 2. Boltzmann Equation BOHRS EQUATION If we consider two quantized energy levels like higher energy as E 2 and low energy as E 1. The radiation given out during the transition from E 2 to E 1 May be expressed by the following equation. E 2 - E 1 = hⱱ h = planks constant ⱱ = Frequency of emitted light Where , ⱱ = c / λ c= Velocity of light λ = wave length of the absorbed radiation

7. E2 – E1 = hc / λ (or) λ = hc / E2 – E1 APPLICATION OF BORHS EQUATION : 1. Wave length of the emitted radiation which is characteristic of the atoms of the particular elements from which it was initially emitted. 2. Wave length of radiation given out from a flame is indicative of the elements that might be present in that flame . BOLTZMANN EQUATION The fraction of the atoms which are excited thermally in other words the relationship between the ground state and the excited state quantum is exclusively represented by the boltzmann equation

8. N 1 /N = (g 1 /g ) e - Δ E/KT Where , N1 = Number of atoms in the excited state ( high energy level) N0 = Number of ground state atoms g1/g0 = Ratio of statistical weights for ground and excited states E = Energy o excitation (= hv ) K = Boltzmann equation T = Temperature ( in kelvin ) 1. Fraction of atoms excited (N1) solely depends upon the temperature of the flame (T). 2. Ratio N1/N0 is dependent upon the excitation energy ( Δ E) . Therefore the fraction of atoms excited critically depends on the temperature of the flame there by emphazing the vital importance of controlling the temperature in flame emission spectroscopy.

9. INSTRUMENTATION / COMPONENTS OF A FLAME PHOTOMETER 1.Burner ( With Fuel And Oxidant) 2.Filter / monochromator 3.Detector 4.Read out device

10. 1.BURNER Which are used to spray the sample solution into fine droplets mix with fuel and oxidant So only the homogenous flame of stable indensity is obtained. TYPES 1.Total consumption burner 2.Laminor flow burner TOTAL CONSUMPTION BURNER

11. LAMINOR FLOW BURNER 2.FUEL AND OXIDENT Ideal combination of oxidant and fuel which gives the desired temperature In the flame photometry.

12. DIFFERENT COMBINATION OF OXIDANT AND FUEL FUEL FLAME TEMPERATURE OXIDANT AIR OXYGEN PROPANE 2100 c 2800 c HYDROGEN 1900 c 2800 c ACETYLENE 2200 c 3000 c 3.FILTER AND MONOCHROMATOR The flame photometer contains a filter wheel (containing several filter for either ( CA,NA,K,LI)When a particular element has to be analyzed the specific filter was selected Filter / monochromator are convert the polychromatic light into monochromatic light.

13. FILTER MONOCHROMATOR Absorption filter Prism type 1.Dispersive(refractive) 2.Littrow(reflective type) Interference filter Grafting type 1.Diffraction 2.Transmission TYPES OF FILTER AND MONOCHROMATORS 1.ABSORPTION FILTER

14. 2.INTERFERANCE FILTER It has dielectric spacer film made up of caF 2 , MgF 2 , or sio 2 between to parallel reflecting film . λ =2nb / m λ = wave length of light obtained n = dielectic constant of layer material b = layer thickness m = order no (0, 1, 2, etc….) The interference filter other wise called as the fabry-perot filter Band pass is 10-15 nm

15. MONOCHROMATORS : monochromator are better and more efficient than filters in converting a polychromatic light to monochromatic light . 1. entrance slit (to get narrow source) 2. collimator (to render light parallel ) 3. Grating or prisms (to disperse radiation ) 4. collimator (to reform the images of entrance slit ) 5. Exit slit (to fall o sample cell ) PRISMS : 1. Refractive type (Dispersive) 2. Reflective type ( Littrow type mountin G ) REFRECTIVE TYPE

16. REFLECTIVE TYPE : The principle of working is similar to the refractive type except that, a reflective surface is present on one side of the prism. Hence the dispersed radiation gets reflected and can be collected on the same side as the source of light GRATING MONOCHROMATOR Grating are the most efficient ones in converting a polychromatic light into monochromatic light in the real sense. 1.Defraction grating 2.Transmission grating

17. 1.DIFFRACTION GRATING Grating are the ruling material like glass , quartz or alkyl halides Depending upon the instrument. When a incident light is passed on the grating the passed lights gets diffracted. Refracted radiation wavelength can be calculated by the equation, m λ = b (sin I ± sin r) λ = wavelength of light produced b = grating spacing I = angle of incident r = angle of reflection m= order (0,1,2,3 etc)

18. 2.TRANSMISSION GRATING This grating is similar to diffraction grating , but refraction takes place instead of Reflection. This occur , when radiation transmitted through grating reinforce with the partially refracted Radiation. The wavelength of radiation produced by transmission grating can be expressed by following equation. λ = dsin θ /m λ = wavelength of radiation produced d= 1/lines per cm m= order no. (0,1,2,3, etc) θ = angle of deflection/diffraction

19. 3.DETECTORS 1.When a radiation is passed through a sample cell, part of its being absorbed by the sample Solution and rest is being transmitted. This transmitted radiation falls on the detectors and the intensity of absorbed radiation can be determined. 2.Detectors are convert the light energy into electrical energy. Which can be read or recorded. TYPES Barrier layer cell or photo voltic cell Photo tubes or photo emissive cell Photo multiplier tubes

20. Detector has a Thin metallic layer coated with silver or gold and acts as a electrodes Metal base plate act as a another electrode when light radiation falls on the selenium layer, these electrons become mobile and are taken up by the transparent metal layer. 4. The flow of current causes deflection of the galvanometer. 5. Which is more sensitive like human eye. 1. BARRIER LAYER CELL OR PHOTO VOLTICCELL

21. 2. PHOTO TUBES OR PHOTO EMISSIVE CELL Composed of evacuated glass tube , which consist of photo cathode and collector anode 2. Cathode coated with caesium, potassium or silver oxide. 3. When a light radiation falls on it electrons are move towards anode produces a current proportional to the intensity of the light radiation. 4. Photo tubes have more sensitivity compared to photo voltic cell.

22. 3.PHOTO MULTIPLIER TUBES(PMT) This is achieved by using a photo cathode and a series of anode( dyanodes ) Upto 10 dyanodes are used each have maintained at 75-100v When a light radiation is passed on to the cathode that can be passed to Serious of anodes,finally electrical signal can be readout by readout device.

23. APPLICATONS OF FLAME EMISSION SPECTROSCOPY Qualitative analysis 2. Quantitative analysis Direct comparison method Calibration curve method standard addition method Internal standard method

24. Flame photometry is used to identify the elements present in the sample solution This is done by peak matching , At least three peaks of emission spectrum should match when sample and standard spectra are recorded. If the calcium emits the radiation at 422nm,554nm,626nm,if the spectrum of the sample Shows maximum emission at these wavelength, then the sample can be identified by standard. 1.QUALITATIVE ANALYSIS

25. 2.QUANTITATIVE ANALYSIS Concentration of the sample can be detect by this method. Following are some of the quantitative applications. Concentration of calcium in serum concentration of sodium , potassium, calcium present in urine assay of potassium chloride in syrup. The amount or concentration of the sample can be calculated by any of following four Methods. Direct comparison method Calibration curve method Standard addition method Internal standard method

26. 1. DIRECT COMPARISON METHOD Which is simple method, the %flame intensity (%FI) of standard solution and sample solution is compared. Concentration in sample solution = % F.I. Of the sample % FI of std × concentration of ion in standard 2. CALIBRATION CURVE METHOD By this method standard solution of the element to be estimated , plot a graph against Concentration vs % flame intensity. PROCEDURE Prepare a stock solution of sodium chloride solution(1000ɥg/ml). From the stock solution prepare serious of standard solution of sodium (10,20,30,40 and 50ɥg/ml).

27. Select the sodium filter in the instrument Calibrate the instrument with the help of distilled water Set 100% flame intensity by using the maximum concentration of standard Solution in the calibration region. Use the other standard solutions as well as sample solution and determine the %flame intensity. Frome the flame intensity of the sample solution, the concentration of ion In the sample solution can be determined.

28. 3.STANDARD ADDITION METHOD This method is used, when the interfering elements cannot be removed or difficult to remove From the sample matrix. Eg : standard addition method is used in the estimation of calcium in magnesium chloride for dialysis Plot a graph against %flame intensity vs concentration of sample solution in x-positive axis and X-negative axis. When a two axis interpolated , meets at negative x-axis ,which is the concentration of The ion present in the given sample solution.

29. 4.INTERNAL STANDARD METHOD This method is used for avoid or minimise the error due to the fluctuation in the flame intensity.The errors in atomising the sample solution due to high viscosity etc... In this method , a known concentration of different element is added to standard solutions As well as to sample solution.

30. REFERENCES Text book of pharmaceutical analysis by DR.S.RAVI SANKAR,4 th edition Text book of pharmaceutical analysis by vidhya sakar .