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Flame A E S
Atomic emission spectroscopy (AES) uses quantitative measurement of optical emission from excited atoms to determine analyte concentration. Analyte atoms are aspirated into an excitation source like a flame, discharge, or plasma which provides energy to promote atoms into high energy levels. As atoms decay back to lower levels, they emit light of wavelengths specific to each element. AES can simultaneously detect multiple elements and is used for elemental analysis, identification, quantification, and sometimes speciation of samples.
Flame A E S
- 1. DR.ATIKAH, MSI JURUSAN KIMIAFMIPA-UB 2011
- 2. Spektrometri emisi atomnyala Spektrometri emisi atom arc-spark Spektrometri emisi atom -ICP
- 3. PENDAHULUAN FES 3 23/11/2010
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- 5. Introduction Atomic emission spectroscopy(AES or OES [optical emission spectroscopy) uses quantitative measurement of the optical emulsion from excited atoms to determine analyte concentration. Analyte atoms in solution are aspirated into the excitation region where they are desolvated, vaporized, and atomized by a flame, discharge, or plasma
- 6. Introduction These high-temperature atomizationsources provide sufficient energy to promote the atoms into high energy levels. The atoms decay back to lower levels by emitting light. Since the transitions are between distinct atomic energy levels, the emission lines in the spectra are narrow The spectra of samples containing many elements can be very congested, and spectral separation of nearby atomic transitions requires a high-resolution spectrometer. Since all atoms in a sample are excited simultaneously, they can be detected simultaneously using a polychromator with multiple detectors. This ability to simultaneously measure multiple elements is a major advantage of AES compared to AAS
- 7. Introduction AES is abroad area that includes several analytical chemistry techniques focused on: elemental analysis, the identification, quantification, and (sometimes) speciation of the elemental makeup of a sample.
- 8. Introduction AES can bean extremely useful tool and is utilized in academic and industrial settings within biological and chemical sciences. It is mainly used in quantitative analysis, but can be used in qualitative work as well
- 9. History and Theory-- Introduction Atomic spectroscopy began with the realization in the mid-19th century that salts in a flame could emit light of wavelength specific to metallic elements introduced to the flame as powders or solutions, and that light of the same wavelength might be missing from emission from stars (including the sun) because the elements absorbed light.
- 10. The figure illustratesthat sodium emits light at 588.9 nm and 589.5 nm (if the atoms are hot enough), or absorbs light if the atoms are cold. "Hot" and "cold" are vague, and the way to know what wavelengths correspond to which elements aren't obvious. We discuss this later. .
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- 14. Bila atom-atomsuatu unsur diletakkan dalam sumber pengeksitasi Ekektron di orbital terluar ( keadaan dasar) tereksitasi ke tingkat energi lebih tinggi Elektron yang tereksitasi berada dalam keadaan tidak stabil Segera kembali ke keadaan dasarnya ( ke tk. Energi lebih rendah) sambil melepaskan kelebihan energi unsur ybs FES 14 23/11/2010
- 15. Kelebihan energiyg dimiliki sewaktu tereksitasi akan dibuang ke luar berupa emisi sinar dengan yang karakteristik untuk unsur ybs X +E X* X + E ( dengan khas ) Emisi yang dipancarkan atom-atom tereksitasi memiliki beberapa macam yg karakteristik untuk unsur ybs & dengan intensitas berbeda FES 15 23/11/2010
- 16. E = 3,6eV 4p E3 3d E2 EMISI 330 nm 819 nm -Dengan beberapa 3p Grs spektrum E1 yang berbeda 589 nm - Intensitas berbeda G 3s E = 2,2 eV FES 16 23/11/2010
- 17. Untuk suatusumber pengeksitasi atom perlu sumber energi yang mampu mengeksitasikan elektron di orbital terluar ke tingkat energi elektron lebih tinggi Proses eksitasi dapat dihasilkan sumber energi : - nyala api gas ( kelemahan ; hasilkn energi bervariasi ) - kombinasi gas (asetilen + udara) hasilkan intensitas sinar emisi yang baik untuk eksitasi logam alkali & alkali tanah pada spektroskopi nyala FES 17 23/11/2010
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- 20. Schematic of anAES experiment
- 21. Atomisasi FES 21 23/11/2010
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- 23. Flame Excitation Source Aflame provides a high-temperature source for desolvating and vaporizing a sample to obtain free atoms for spectroscopic analysis. In atomic absorption spectroscopy ground state atoms are desired. For atomic emission spectroscopy the flame must also excite the atoms to higher energy levels. The table lists temperatures that can be achieved in some commonly used flames.
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- 26. Instrumention The figure showsa total consumption burner in which the sample solution is directly aspirated into the flame. This flame design is common for atomic emission spectroscopy. All desolvation, atomization, and excitation occurs in the flame. Other flame designs nebulize the sample and premix it with the fuel and oxidant before it reaches the burner. Atomic-absorption instruments almost always use a nebulizer and also use a slot burner to increase the path length for the sample absorption
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- 28. PEMANCARAN SINAR KHAS ( TERTENTU) ANALISIS KUALITATIF MEMUNGKINKAN HUBUNGAN ANTARA SINAR YANG DISERAP & KONSENTRASI ANALISIS KUANTITATIF FES 28 23/11/2010
- 29. T = I/ Io = e -kbc A= - log T = -log I / Io = log Io / I = ab c FES 29 23/11/2010
- 30. KETERANGAN: I = INTENSITAS CAHAYA SETELAH MENGALAMI ABSORPSI ; Io = INTENSITAS CAHAYA SEBELUM ABSORPSI ; k = SUATU TETAPAN ; b = TEBAL LAPISAN PENGABSORPSI ; c = KADAR ATOM DALAM LAPISAN PENGABSORPSI ; a = KOEFISIEN ABSORPSI ; A = ABSORBANSI FES 30 23/11/2010
- 31. KEUNTUNGAN FES 31 23/11/2010
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