Ceram. Characterization: Asst. Prof. Dr. S. T. Rattanachan 1 AAS,AES,ICP 426306 Ceramic Characterization Part: Atomic Absorption Spectroscopy (AAS), Atomic Emission Spectroscopy (AES), Inductively Coupled Plasma Spectroscopy (ICPs) (2 hrs.) Asst. Prof. Dr. Sirirat T. Rattanachan School of Ceramic Engineering
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Ceram. Characterization:Asst. Prof. Dr. S. T. Rattanachan 1AAS,AES,ICP
Ceram. Characterization:Asst. Prof. Dr. S. T. Rattanachan 8AAS,AES,ICP
Electromagnetic radiation
• Electromagnetic radiation ���ก0!"��������+��+(*#�����+�)�ก�,��ก#� ��������ก0!"�� an oscillating electric field component, E ��� an oscillating magnetic field component, M ��������� ���ก����������������ก����ก����ก� ������������������กก����������ก !�"�����#��$% ��&'(� &���� �"��$% �� !�"������%����ก ��� ��#��ก ������(���!"�!(�)�� ��������(� %* s-1 � "� Hertz
Ceram. Characterization:Asst. Prof. Dr. S. T. Rattanachan 9AAS,AES,ICP
()���+� ������ *����+$.��+(*#����(!+�+����%�"��� Na �ก�!ก����*+��������.�ก�'���(�$� ��-,�'���ก����"�)
��!#0(*#�������� 11Na23 (1S2, 2S2, 2P6, 3S1)
3s
589 nm330.0 nm
3p 2.2 ev
3.6 ev4p
Ground state (o.o)
Ceram. Characterization:Asst. Prof. Dr. S. T. Rattanachan 16AAS,AES,ICP
Spectroscopy
• Spectroscopy is the use of the absorption, emission, or scattering of electromagnetic radiation by matter to qualitatively or quantitatively study the matter or to study physical processes. The matter can be atoms, molecules, atomic or molecular ions, or solids. The interaction of radiation with matter can cause redirection of the radiation and/or transitions between the energy levels of the atoms or molecules.
• Absorption: A transition from a lower level to a higher level with transfer of energy from the radiation field to an absorber, atom, molecule, or solid.
• Emission: A transition from a higher level to a lower level with transfer of energy from the emitter to the radiation field. If no radiation is emitted, the transition from higher to lower energy levels is called nonradiative decay.
• Scattering: Redirection of light due to its interaction with matter. Scattering might or might not occur with a transfer of energy, i.e., the scattered radiation might or might not have a slightly differentwavelength compared to the light incident on the sample.
http://www.chem.vt.edu/chem-ed/spec/spectros.html
Ceram. Characterization:Asst. Prof. Dr. S. T. Rattanachan 17AAS,AES,ICP
ก����*+������������ �.�ก�! !" 3 )00
E0
Ej Atomic Absorption Spectroscopy��*:ก����*+�����!#0(*#����.�ก�����(�$� ��#������ก����"�)�ก�!�ก��!-!ก*��(*#����.�ก�1��Absorption of radiation νjo = (Ej – Eo)/h
• A = log (I0/I) = kν Lc log e• I = I0 exp (-kν Lc)
A = AbsorbanceI0 = ความเขมของแสงที่เขามา I = ความเขมของแสงที่ผานเปลวไฟออกไปkν = คาสัมประสิทธิการดูดกลืนแสง L = ระยะทางที่แสงผานเปลวไฟ หรือบริเวณที่มีการแตกตัวของอะตอม หรืออิออน c = ความเขมขนของอะตอม
Ceram. Characterization:Asst. Prof. Dr. S. T. Rattanachan 23AAS,AES,ICP
• Io/I = exp kν Lc• ln Io/ I = kνLc• log (Io/I) = (kν/2.303) x Lc• เมื่อ kν/2.303 = K • log (Io/I) = K Lc• หรือ A = log (Io/I) = K Lc เมื่อ A= absorbance• แตความเขมขนของอะตอมจะเปนสดัสวนโดยตรงกับความเขมขนของ
ธาตุทีต่องการวิเคราะห โดยมีความสัมพันธดงันี้ • c = aC• เมื่อ a = สัมประสทิธิ์การเกิดเปนอะตอมอิสระ • C = ความเขมขนของธาตุทีต่องการวิเคราะห• ดังนั้น ln Io/ I α Total absorption• Total absorption = integral ของ kν ตลอด spectral range ของ
absorption lines•
Ceram. Characterization:Asst. Prof. Dr. S. T. Rattanachan 24AAS,AES,ICP
• �#��#=� Total absorption >?=���!�ก#8�@����������������"=� $�� Nj �� ��������"������8ก#8 No �#��#=� No �?�$17#���ก#8�@���������#=���� $%1���(>��4��&�������ก�������%%�� $% ����>��>��>����%%�� Log Io / I α No �"� Absorbance α ����>��>��>����%%��
• Common discharge lamps and their wavelength ranges are:hydrogen or deuterium : 160 - 360 nmmercury : 253.7 nm, and weaker lines in the near-uvand visibleNe, Ar, Kr, Xe discharge lamps : many sharp lines throughout the near-uv to near-IRxenon arc : 300 - 1300 nm
Ceram. Characterization:Asst. Prof. Dr. S. T. Rattanachan 28AAS,AES,ICP
Ceram. Characterization:Asst. Prof. Dr. S. T. Rattanachan 54AAS,AES,ICP
Mass spectroscopy
• Introduction
• Mass spectrometers use the difference in mass-to-charge ratio (m/e) of ionized atoms or molecules to separate them from each other. Mass spectrometry is therefore useful for quantitation of atoms or molecules and also for determining chemical and structural information about molecules. Molecules have distinctive fragmentation patterns that provide structural information to identify structural components.
• The general operation of a mass spectrometer is:• create gas-phase ions • separate the ions in space or time based on their mass-to-charge ratio • measure the quantity of ions of each mass-to-charge ratio • The ion separation power of a mass spectrometer is described by the
resolution, which is defined as:R = m / m,where m is the ion mass and m is the difference in mass between two resolvable peaks in a mass spectrum. E.g., a mass spectrometer with a resolution of 1000 can resolve an ion with a m/e of 100.0 from an ion with an m/e of 100.1.
Ceram. Characterization:Asst. Prof. Dr. S. T. Rattanachan 55AAS,AES,ICP
Terms for the analytical technique and spectral radiation
• Characteristic radiation: Radiation which is specifically emitted or absorbed by free atoms of the given element.
• Resonance line: the emission of an atomic line is the result of a transition of an atom from a state of excitation is the ground state, the line is called the resonance line.
• Hollow cathode lamp: A discharge lamp with a hollow cathode used in atomic spectrometry to produce characteristic radiation of the elements to be studied. The cathode is usually cylindrical and made from the analyst element or contains some of it.
• Electrodeless discharge lamp (EDL): This is a tube which contains the element to be measured in a readily vaporized form.A discharge is produced in the vapor by microwave or radio frequency induction. The lamp emits very intensive characteristic radiation of the analyst.
• Plasma: Partly ionized gas (ex. Argon) which contains particles of various types (electrons, atoms, ions and molecules) maintained by an external field.
Ceram. Characterization:Asst. Prof. Dr. S. T. Rattanachan 56AAS,AES,ICP
• Self-absorption: the radiation emitted by the atoms of a given element is absorbed by the atoms of the same element in a spectral source.
• Matrix: The chemical environment of the element to be determined.
• Matrix effect: An interference caused by the difference between the sample and the standards.
• Sample solution: A solution made up from the test portion of the sample for the analysis.
Terms for the analytical technique and spectral radiation
Ceram. Characterization:Asst. Prof. Dr. S. T. Rattanachan 57AAS,AES,ICP
• Standard: A solution containing a known concentration of the analyze in the solvent and other major constituents in proportions similar to those in the sample.
• Blank: A blank test solution containing all the chemicals in the same concentrations as required for the preparation of the sample solutions, except the analyze.