1. 원자흡수분광분석법
(원리및 응용)

2. 차 례 Optical Spectra의 역사 원자분광분석법의 기본원리 원자흡수분광기의 구조 원자흡수분광기의 기기적 특성
차 례
Optical Spectra의 역사
원자분광분석법의 기본원리
원자흡수분광기의 구조
원자흡수분광기의 기기적 특성
AAS의 측정
AAS의 오차
Flame vs Furnace AAS의 비교
다른 원자분광분석기와의 비교
AAS의 응용

3. Early History of Optical Spectra
Sir Isaac Newton discovers the solar spectrum in the late 1600’s
Sunlight
Prism

4. Fraunhofer Lines
1802 Wollaston discovered dark lines in solar spectrum
Fraunhofer investigated lines in detail
Lines due to sundown atmosphere absorbing light

5. Kirchhoff & Bunsen’s Experiment (1)
Light Source
Burner
Prism
White
Card
Place Salt on Wire Loop
and Hold in Flame
Lens
Dark
Lines

6. Kirchhoff & Bunsen’s Experiment (2)
Used to Discover the
Elements Rb and Cs
Place Salt on Wire Loop
and Hold in Flame
Lens
White
Card
Burner
Emission
Lines
Prism

7. Absorption vs Emission
Fraunhofer
Absorption
Lines Cu Ba Na K
Elemental
Emission
Lines
190 nm
900 nm
Qualitative analysis of elements

8. Alan Walsh

9. Ground State Atom
Orbitals
Neutrons
Protons
Electrons

10. Absorption of Energy by Atom
Valence (Outer)
Electrons
Excited State
Atom h
Energy
Absorbed
Ground State
Atom

11. Energy Level Diagram Electron Energy Transitions E4 E3 E2 E1 Eo5 6
Resonance lines originate from ground state (Eo)

12. Atomic Absorption Process
Sunlight
Sun Atmosphere
Energy Transitions E3 E2 E1 Eo 3 2 1 4 1 2 3 4
Resonance lines must originate from ground state

13. Energy Level Diagram for Pb
Electron Energy Transitions E4 E3 E2 E1 Eo
202.2
217.0
261.4
283.3
Wavelength in Nanometers

14. Absorption Energy Diagram (Few Lines/Element)
Excitation E
Ionization E3 }
Excited
States E2 c
Energy E1 b
a b c d a
Eo Ground State

15. Emission Energy Diagram (Many Lines/Element)
Ionization E3 }
Excited
States E2 c
Energy E1 b
a b c d a
Eo Ground State

16. Atomic Absorption Spectrometry
AAS intrinsically more sensitive than AES
Similar atomization techniques to AES
Addition of radiation source
High temperature for atomization necessary :
Flame and Electrothermal atomization
Very high temperature for excitation not necessary
Generally no plasma/arc/spark AAS

17. Atomic Absorption Io It
Resonance
Non-resonance
Fill Gas
Resonance

18. Flame AAS Simplest atomization of gas/solution/solid
Laminar flow burner – stable “sheet” of flame
Flame atomization best for reproducibility
Precision (<1%)
Relatively insensitive – incomplete volatilization,
Short time in beam

19. Laminar Flow Burner
Cheap
Simple
Flame stability
Low temperature

20. Flame Temperatures

21. Temperature Profiles of Natural gas/Air Flame
Primary combustion zone:
Initial decomposition, molecular
fragments, cool
Interzonal region:
Hottest, most atomic fragments,
Used for emission/fluorescence
Secondary combustion zone:
Cooler, conversion of atoms to
Stable molecules, oxides

22. Flame Absorbance Profile for Three Elements
Most sensitive part of flame for
AAS varies with analyte
Consequences?
Sensitivity varies with element
Must maximize burner position
Makes multielement detection
difficult

23. Electrothermal Atomizer
Entire sample atomized in short time (2000 – 3000 oC)
Sample spends up to 1 s in analysis volume
Superior sensitivity (10-10 – g analyte)
Less reproducible (5 – 10 %RSD)

24. Types of Graphite Furnace
Graphite tube with L’vov platform
Solid Sampling Accessory

25. Graphite Furnace Cross Section
External Ar gas prevents tube destruction
Internal Ar gas circulates gaseous analyte

26. Four Step Sample Preparation
Dry – evaporation of solvents (10 - >100 s)
Ash – removal of volatile hydroxides, sulfates,
carbonates etc. ( s)
(3) Fire/Atomizer – atomization of remaining
analyte (1 s)
(4) Clean Out

27. Furnace Thermal Stages
Dry
Ash
Atomize T E M P
T I M E
Clean
Out
Cool
Down

28. Periodic Table H He Li Be B C N O F Ne Furnace Only
Na Mg Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac
Furnace Only
Flame & Furnace
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

29. Atomic Absorption Instrumentation
AAS should be very selective – each element has different
set of energy levels and lines very narrow
BUT for linear calibration curve (Beer’s Law) need
bandwidth of absorbing species to be broader than that of
light source : difficult with ordinary monochromator
Solved by using very narrow line radiation sources
Minimize Doppler broadening
Pressure broadening
Lower P and T than atomizer

30. Hollow Cathode Lamp
300 V applied between anode (+) and metal cathode (-)
Ar ions bombard cathode and sputter cathode atoms
Fraction of sputtered atoms excited, then fluoresce
Cathode made of metal of interest (Na, Ca, K, Fe,…..)
Different lamp for each element
Restricts multielement detection
Hollow cathode to
Maximize probability of redeposition on cathode
Restricts light direction

31. Multi-element HCL lamps

32. Pneumatic Nebulizers
Concentric tube
Cross-flow
Fritted disk
Babington

33. Single-beam Design AA Spectrometer
Signal at one wavelength often contains luminescence from interferent in flame
Chemical interference:
reverses atomization equilibria
reacts with analyte to form low volatile compound
Releasing agent – cations that react preferentially with interferent
Protecting agent – form stable but volatile compounds with analyte
ionization

34. Double-beam Design AA Spectrometer
Spectral interference -
emission or absorption from
interferent overlaps analyte
Beam usually chopped or
modulated at known frequency
Signal then contains constant
(background) and dynamic
(time-varying) signals

35. Echelle Monochromator
Echelle grating with a prism,
Focal plane

36. Multielement Instruments
Hitachi design
Multiple HCLs with multiple
detection systems

37. Thermo Jarrell Ash Design Perkin-Elmer Design
Multiple HCLs with one monochromator and PMT with a mirror and grating controlled by a galvanometer
Multiple HCLs with an echelle monochromator
and a CCD detector

38. Leeman Lab. Design SIMAAC Design
Multiple HCLs arranged on the focal plane
of the grating
Continuum source excitation with
a monochromator and PMT

39. Photomultiplier Tube (PMT)

40. Solid State Detector

42. Beer-Lambert Absorbance CalculationIt
A = log ( ) = abc A c
Where:
A = Absorbance a = absorptivity
Io = Incident Light Intensity b = path length
It = Transmitted Light Intensity c = concentration

43. Beer-Lambert Law
Theoretical
A = abc A B S
Actual
abc A
CONC

44. % Transmittance vs ABS Transmittance Absorbance 10 % 1 1 % 2 0.1 % 3
100 %
10 %
1 %
0.1 %

45. Flame vs Furnace Sensitivity
100 g/L nm
0.936
Furnace Signal
for 10 L
Absorbance
Flame Signal
0.004

46. Flame vs Furnace AAS Criteria Flame Furnace Elements 67 48
Sensitivity ppm-% ppt-ppb
Precision good fair
Interferences few many
Speed rapid slow
Simplicity easy more complex
Flame Hazards yes no
Automation yes yes (unattended)
Operating Cost low medium

47. Flame vs Furnace Detection Limit Comparison
Element Flame (PPB) Furnace (PPB)* Ag As Bi Cd Cr Pb Zn
*Results Based on 20 L Volume & D2 Peak Height ABS

48. Hydride Generation Techniques
A method for introducing samples
containing arsenic, antimony, tin,
selenium, bismuth, and lead into
an atomizer as a gas
Enhances D.L. by a factor of 10 to
100.
3BH4- + 3H+ + 4H3AsO3
3H3BO3 + 4AsH H2O

50. Continuum-source Correction
Alternate pass through:
Continuum source of D2
and HCL radiation
And then subtract
AHCL – AD2 = Ac

51. Zeeman Background Correction
The  peak absorbs only the radiation that is plane polarized in a direction
parallel to the external magnetic field
The  peaks absorb only radiation polarized at 90 deg to the field
A// – A = Ac

52. Smith-Hieftje Background Correction
Based on self-reversal or
self-absorption
A low current – A high current = Ac

53. AA vs. ICP-AES vs. ICP-MS: 비 교 표

54. 기기에대한 결정 인자
분석시 샘플형태
분석물질의 농도
샘플 전처리정도
예 산
운용 유지비
분석상황

55. 분 석 시 샘 플 형 태 액 상 고 상 (슬러지) 고상형태 (직접주입) Flame AA Vapor Generation AA
분 석 시 샘 플 형 태
액 상
Flame AA
Vapor Generation AA
Graphite Furnace AA
ICP-AES
ICP-MS
고 상 (슬러지)
고상형태 (직접주입)
고가의 악세사리(스파크 또는 레이저 시스템)

56. 용 융 고 체 분 석 시 용융 고상함유% Vapor Generation GFAA Flame AA ICP-AES ICP-MS
용 융 고 체 분 석 시 용융 고상함유%
Vapor Generation
GFAA
Flame AA
ICP-AES
ICP-MS
% Solids

57. 샘 플 효 율

58. 원 자 화 / 이 온 화 효 율

59. 최 소 샘 플 주 입 량

60. # 분 석 가 용 원 소 Vapor Generation GFAA Flame AA ICP-AES ICP-MS
# 분 석 가 용 원 소
Vapor Generation
GFAA
Flame AA
ICP-AES
ICP-MS
# Elements

61. 분 석 감 도 Vapor Generation AA GFAA Flame AA ICP-AES ICP-MS
분 석 감 도
Vapor Generation AA
GFAA
Flame AA
ICP-AES
ICP-MS
ppt ppb ppm
ng/L mg/L mg/L

62. 직 선 동 적 범 위 Vapor Generation GFAA Flame AA (SIPS) ICP-AES
직 선 동 적 범 위
Vapor Generation
GFAA
Flame AA
(SIPS)
ICP-AES
ICP-MS
(Extended Range)
Linear Dynamic Range

63. 재 현 성 %RSD 5
GFAA
Vapor
Gen.
ICP
%RSD
Flame AA
ICP-MS -5

64. 샘 플 주 입 량

65. 분석 가용원소수 vs 농도 high Flame AA ICP-AES conc GFAA ICP-MS low low high
Vapor Generation
low
low
high

66. 요구되는 분석자의 능력 분 석 개 발 정 도 High Difficult ICP-MS Skill Level ICP-AES
Moderate
GFAA
Vapor
Gen
Flame AA
Easy
Low

67. 간 섭 :분광학적(Spectral) High ICP-AES Degree of Interference Flame AA Vapor
Gen
GFAA
ICP-MS
Low

68. 간 섭 :주변물질(화학적l/물리적) High GFAA Degree of Interference Vapor Gen Flame
ICP-MS
ICP-
AES
Low

69. 간 섭 : 이 온 화 (Ionization) High Degree of Interference Flame AA ICP- AES
Vapor
Gen
GFAA
ICP-MS
Low

70. 예 산 Vapor Generation Hg Analyzer GFAA Flame AA ICP-AES (Sequential)
예 산
Vapor Generation
Hg Analyzer
GFAA
Flame AA
ICP-AES (Sequential)
(Simultaneous)
ICP-MS
$$ x 1,000

71. 운 용 유 지 비
High
ICP-
AES
ICP-MS
GFAA
Expense
Vapor
Gen
Flame AA
Low

72. 분 석 비 용 25 개 원소 분석시 High GFAA Cost/Analysis Can do 25 elements
분 석 비 용 25 개 원소 분석시
High
GFAA
Cost/Analysis
Can do 25 elements
by vapor generation
ICP-
AES
ICP- MS
Flame AA
Low

73. 장 점 비 교(1) 원자흡수분광법(Flame & Furnace) 유도쌍 플라즈마법 (ICP-AES) 낮은분광학적간섭
장 점 비 교(1)
원자흡수분광법(Flame & Furnace)
낮은분광학적간섭
좋은 정밀도
사용이 용이
낮은 운용 유지비
적은예산에적합
유도쌍 플라즈마법 (ICP-AES)
효율적인원자여기상태
적은주변물질의 간섭
운용시 쉽게 접근
신속한 다원소분석
넓은 동적범위

74. 장 점 비 교 (2) 유도쌍플라즈마 질량분석기 (ICP-MS) 증기 원자화장치 (Vapor Generation)
신속한 다원소분석
낮은 검출한계
월등한 동적범위
낮은 분광학적 간섭
동위원소 분석
증기 원자화장치 (Vapor Generation)
호한성: AA, GFAA, ICP or ICP-MS
적은 간섭

75. 단 점 비 교 (1) 원자흡광분광광도계 (Flame and Furnace) 유도쌍 플라즈마법 (ICP-AES)
단일 원소 분석법
화학적 간섭
한정된 동적범위
가연성 가스 사용(flame)
유도쌍 플라즈마법 (ICP-AES)
분광학적 간섭
공간-의존 간섭(Spacial-dependent interferences)
고가의 운용비용(Ar소모)
고가의 장비

76. 단 점 비 교(2) 유도쌍 플라즈마 질량분석기 (ICP-MS) 증기 원자화 장치 (Vapor Generation)
주변물질의 간섭
동중체(같은질양)간섭 떨림
크린룸이 필요
고가 장비
증기 원자화 장치 (Vapor Generation)
7가지원소에 한정
화학적 추출 전처리

77. The analysis of cement

78. Cold vapor determination of Hg

79. Cr in Saline water by GFAAS

81. Cr in urine sample
Magnesium nitrate was used as a matrix modifier Zeeman background correction was used.

83. ETV-FAAS
Pb in blood
sample

84. Impaction GFAAS