1 / 28

ATOMIC ABSORPTION SPECTROMETER

ATOMIC ABSORPTION SPECTROMETER. SELİN CANSU ÖZTÜRK ŞEYMA ATAKUL SEZİN GÜNER. ATOMIC ABSORPTION SPECTROMETER. Introduction Invention Working Principle of AAS Instrumentation Interferences & Correlation Methods Applications. INVENTION.

adem
Télécharger la présentation

ATOMIC ABSORPTION SPECTROMETER

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. ATOMIC ABSORPTION SPECTROMETER SELİN CANSU ÖZTÜRK ŞEYMA ATAKUL SEZİN GÜNER

  2. ATOMIC ABSORPTION SPECTROMETER • Introduction • Invention • WorkingPrincipleof AAS • Instrumentation • Interferences & CorrelationMethods • Applications

  3. INVENTION • Introduced in 1955 by Alan Walsh in Australia • Firstlyusedformining, medicaltreatment&agriculture • Alan Walsh(1916-1998) http://www.science.org.au/academy/memoirs/walsh2.html

  4. PROPERTIES OF AAS • Themostwidelyusedmethod in analysis of elements • Based on theabsorption of radiation • Sosensitive (ppb) • Quantitativeanalysis

  5. WORKING PRINCIPLE OF AAS • Electronspromotetohigherorbitalsfor a shortamount of time byabsorbing a energy • M + hv →M* • Relises on Beer-Lambert Law A= a.b.c

  6. INSTRUMENTATION www.scientificlib.com

  7. LIGHT SOURCES HollowCathodeLamps • Anot-Tungsten wire • Cathodemadefromthe element of interest (Na,K,Ca..) • Argon or neon gas http://www.safir.be/AAS.ht

  8. LIGHT SOURCES ElectrodelessDischargeLamp • Typically argon gas at lowpressure • Narrowerlinewidth • Not prefered www.freepatentsonline.com

  9. ATOMIZATION • Compoundsmakingupthesamplearebrokenintofreeatoms. • High temperature is necessary • Basic twotypes -Flameatomizer -Electrothermalatomizer

  10. TYPES OF ATOMIZERS FLAME ATOMIZER • Simplestatomization • Convertsanalyteintofreeatoms of vaporphase • Flammable &causticgases • Not has an inertmedium(−) • Shortanalysis time (−)

  11. TYPES OF ATOMIZERS ELECTROTHERMAL ATOMIZER • A cylindiricalgraphitetube • Inertgasmedium (Argon gas) • Longeranlaysis time thanflame • Superiorsensitivity, highaccuracy

  12. MONOCHROMATOR • Alsoit is calledwavelenghselector • Select thespecificwavelenght • Polychromaticlight →monochromaticlight • Simple one is enoughfor AAS

  13. DETECTOR • Electromagneticwaves→ electriccurrent • ThemostusedonePhotomultipliertube • Havefastresponsetimes www.answers.com

  14. CALIBRATION TECHNIQUES • Two main techniques • Calibrationcurvemethod • Standart additionmethod

  15. CALIBRATION TECHNIQUES CALIBRATION CURVE METHOD • Draw a graph • Havetwoormorevariables -One is set at knownvalues -One is measuredresponse • Most convenient fora large number of similar samplesanalysis.

  16. CALIBRATION TECHNIQUES An example of calibrationcurvemethod

  17. CALIBRATIONTECHNIQUES STANDART ADDITION METHOD • To measure the analyte concentration in a complexmatrix. • Most convenient for small number of samplesanalysis • Preventeffect of chemical & spectralinterferences

  18. INTERFERENCES • Causes higherorlowerabsorbancevalue • Twomajorgroups • ChemicalInterferences • SpectralInterferences

  19. CHEMICAL INTERFERENCES • Themostcommonone in flameatomizer. • Consequence of chemicalreactions. • Reduceamount of oxygen in flametoovercome

  20. SPECTRAL INTERFERENCES • Absorptionoremission of theradiation at thesamewavelength • Radiationwhich is absorbed→pozitiveerrors • Radiationwhich is emmitted→negativeerrors

  21. SPECTRAL CORRELATION METHODS TWO-LINE CORRELATION METHOD • Select twoline • characteristicwavelength of analyte • veryclosetoanalyteline but not absorbedbyanalyte • Measurethedifferencebetweentwolines

  22. SPECTRAL CORRELATION METHODS CONTINUUM SOURCE CORRELATION METHOD • Select twolamps • Deuteriumlamp & hollowcathodelamp • Whenhollowcathodelamp is used total absorbace is measured • Whendeuteriumlamp is usedonly background absorption is measured • Measurethedifferencebetweentwolines.

  23. SPECTRAL CORRELATION METHODS ZEEMAN EFFECT CORRELATION METHOD • Presence of magneticfield. • Splitting of spectrallines.

  24. CONCLUSION • One of themostimportanttechnique in quantitativeanalysis • It is based on theabsorption of radiation • Measurementscould be done at ppblevels • It’swidelyusedmethod • Thepreparation of thesample is usuallysimpleandrapid

  25. CONCLUSION • Therearemanyadventages • High sensitivity [10-10 g (flame), 10-14 g (non-flame)] • Goodaccuracy (Relativeerror 0.1 ~ 0.5 % ) • Highselectivity

  26. APPLICATIONS OF AAS • Water analysis (e.g. Ca, Mg, Fe, Si, Al, Ba content) • Foodanalysis • Analysis of animal feedstuffs (e.g. Mn, Fe, Cu, Cr, Se,Zn) • Analysis of soils • Clinicalanalysis (bloodsamples: wholeblood, plasma,serum; Ca, Mg, Li, Na, K, Fe)

  27. REFERENCES • http://www.scribd.com/doc/10513921/Atomic-Absorption-Determination-of-Zinc-and-Copper-in-a-Multivitamin • http://www.hemlin.pp.se/USstarten.html • http://www.learn-english-today.com/business-english/presentations-phrases.htm

  28. THANKS FOR YOUR ATTENTION..

More Related