ICP-MS 基本原理 陳麗真 Jennifer Chen Inorganic Products Specialist Email:Jennifer.Chen@perkinelmer.com
What is the ICP-MS Inductively Coupled Plasma Mass Spectrometry can analyze almost all elements in the periodic table at concentration of 1 ppm = 1 mg/l = 1 μg/ml = 10-6 g/ml 1 ppb = 1 μg/l = 1 ng/ml = 10-9 g/ml 1 ppt = 1 ng/l = 1 pg/ml = 10-12 g/ml 1 ppq = 1 pg/l = 1 fg/ml = 10-15 g/ml Other similar techniques: Atomic Absorption Spectroscopy (AAS) Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES)
Atom He Atomic number = 2 Atomic weight = 4.002602 g Electron cloud Proton 1,840 electrons - - -- --- - + - - - - - - - - -- - Electron - Nucleus + + Proton - Neutron Proton + Neutron
Isotope and Isobar Fe Atomic number = 26 Atomic weight = 55.845 g Ni Atomic number = 28 Atomic weight = 58.6934 g Isotopes Abundance(%) Protons Neutrons Electrons 54 Fe 5.845 26 28 26 56 Fe 91.754 26 30 26 57 Fe 2.119 26 31 26 58 Fe 0.282 26 32 26 58 Ni 68.0769 28 30 28 60 Ni 26.2231 28 32 28 61 Ni 1.1399 28 33 28 62 Ni 3.6345 28 34 28 64 Ni 0.9256 28 36 28
ICP-MS Spectrum 1 ppb Pb Photocurrent (Amperes) -5 10-6 10-7 10-8 10-9 10 1 Pb 100mg/L Pb isotopes 4 7 8 9 5 6 3 2 10 11 12 190 210 230 250 270 290 310 330 350 Wavelength (nm)
Elements Analyzed by ICP-MS - D.L. of ELAN DRC - 1A 2A 3B 4B 5B 6B 7B 8B 8B 8B 1B 2B 3A 4A 5A 6A 7A 8A H Inductively Coupled Plasma Mass Spectrometry Li Be B C N O F Ne 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 He Fr Ra Ac Lanthanoid Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Actinoid Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr D.L. range < 1 ppt 1 100 ppt 0.1 1 ppb Other similar techniques: Atomic Absorption Spectroscopy (AAS) Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES)
ELAN Product History ELAN Series Page 7
Schematic Diagram of ICP-MS : ELAN 9000 Main Q-pole DC + AC ( U + Vcosωt ) ShadowStop + + + + + + + Detector Ar gas in Pre-filter AC only ( Vcosωt ) E-Lens Turbomolecular pumps Roughing pumps
Schematic Diagram of ELAN DRC Main Q-pole DC + AC ( U + Vcosωt ) DRC DC + AC ( U + Vcosωt ) Vent valve Gas inlet Shadow Stop + + + + + + Detector Ar gas in Pre-filter AC only ( Vcosωt ) Turbomolecular pumps Roughing pumps E-Lens Axial Field Gradient DC
ELAN ICP-MS System 主要結構 Sample Introduction System Ionization Source Ion Extraction System Ion Focusing System Mass Filter Ion Detection System Control Software Page 10
Components of the ELAN 9000 Mass Filter Plasma Spectrometer Interface Ion Lens ICP Torch Spray Chamber Electron Multiplier Sample Argon Turbo Pump Mech. Pump Mech Pump RF Supply ICP-MS Computer and Control Electronics Page 11
Elan 9000 Major Subsystems Interface Region Mass Filter and Ion Optics Area Sample Introduction System ICP Power Supply (RF Generator) Vacuum Pump System Page 12
ICP-MS -sample introduction Mass spectrometer ICP Detector Interface Sample........... Page 13
Pneumatic Nebulizers Concentric nebulizer Cross flow nebulizer Sample Sample Ar nebulizer gas Ar nebulizer gas
Cross-Flow Nebulizer Standard for ELAN DRCe Uptake 0.5-1.5 ml/min. Good general purpose HF resistant Inexpensive Resistant to clogging Page 15
Sample Introduction Device To generate sample droplets by nebulization and to introduce only fine droplets in the plasma. Sample solution Nebulizer To ICP Ar carrier gas
Sample Introduction Device ( Cyclon spray chamber ) Nebulizer generates small droplets. Spray chamber eliminates larger droplets and introduces only fine droplets into ICP. To ICP Nebulizer To drain
Droplet Size Distribution and Effect of Spray Chamber (%) 50 40 30 20 10 No Spray Cham be r (%) 30 25 20 15 10 5 with Spray Ch a m b e r 0 8 142026323844505662687480 Particle Size ( um ) 0 2 3 4 5 6 7 8 9 10 11 Particle Size ( um)
PFA Sample Introduction System
Plasma Torch, Injector, and Load Coil Assembly Check concentricity of torch and RF coil Use torch alignment tool Tool should move freely Check Sampling Depth Check torch for deposits and discoloration Soak in acid to clean Check for thermal deformation Replace as necessary Check injector and adapter Page 20
Plasma RF 40.68 True Power Control feedback system to control output power provides excellent stability
Ionization Efficiency of Elements in Ar Plasma - Saha equation - a 1 - a = ( 2 p mk T ) Neh 3 3 2 2 Z + Z e V k T a : Ionization efficiency Ne: Electron density m : Mass of an ion V : Ionization potential of an element k : Boltzman constant T : Electron temperature h : Plank constant Z : Partition function
Ionization Efficiency of Elements in Ar Plasma Ionisation efficiency (%) 100 80 60 40 20 0 Li Be B Ru Na Al K ScVMnCo Ga Rb Y Nb Pd In Cs Lanthanoides Hf Tl Pb Ra Mg Si P S Ca Ti Cr Cu Fe Ge Ni Zn As Se C O Ne Cl Ar Br Xe Sr Sn Zr Tc Ba Ta Mo RhAg W Cd Sb Te I 0 He 10 20 30 40 50 60 70 80 90 N F Kr Electron temperature : 6,680K Atomic number Re Bi Po Ac Os Pt Au Rn Hg Ir Electron density : 1.47 14 x 10 cm -1
Ionization efficiency of elements in Ar plasma 100 10 Inonizatoin Efficiency (%) 1 0.1 0.01 0.001 0.0001 0.00001 0.000001 Li Be Mg Cl Ar Fe As 0.0000001 4,500 5,000 5,500 6,000 6,500 7,000 7,500 Electron Temperature (K) Electron density: 5 x 10 13
ELAN DRC Plasma Magnetic field Auxiliary gas Nebulizer gas + sample droplets Plasma Eddy current Plasma gas RF coil
Plasma Ionisation Source To desolvate, decompose, atomise and ionise fine sample droplets. Auxiliary gas Carrier gas + Sample Auxiliary gas Plasma gas Wok coil Magnetic field
電漿形成過程
Ionization Process in Plasma Aerosol Particles Molecule Atom Ion Ca(OH) 2 Ca Ca + Nebulization Desolvation Vaporization Dissociation Ionization
Ion Distribution in Plasma Relative Ion intensity (%) 100 80 60 40 20 Ca Ar 0-8 -6-4 -2 0 2 4 6 8 Distance from the torch center
ELAN RF Generator Fully computer-controlled and autotuned 40-MHz free-running generator handles widely varying sample matrices, including organics PlasmaLok grounding system to ensure seamless analysis of wide range of sample types
First Ionization Potential of Elements (ev) 25 He Ne He 24.58eV 20 Ionisation potential 15 10 5 F N O C Be B Li Ar Kr Xe Cl Br P I Fe Zn As Ir Mg S Mn Co Se Mo Ru Cd Pd Sb Os Ti Si Ca Ge Y Zr Te Ta Lanthanoides Pt Cu Ag W Cr Ni Nb Rh Sn Hf Al Sc Ga Re Sr Tc In Na Ba K V Rb Cs Au Hg Po Pb Tl Bi Rn Ra Ac Ar 15.75eV 8 ev 0 0 10 20 30 40 50 60 70 80 90 Atomic number
Sampling ions through interfaces Sampling cone Direction of ions and neutral species gathers by expansion of plasma through sampling cone. Mach disk Shadow stop Na + e- Ar Ar Na + e- Ar Na + e- e- e- Ar Ar Na + Ar e- Na + e- e- e- e- e - Na + Ar Na + Ions and neutral species and elencrons are randamly moving in the plasma Vacuum Skimmer cone AutoLens
ELAN DRCe Interface New quick-change sampler and skimmer cones Ni is standard. Large diameter orifices to minimize clogging Sampler - 1.1 mm Skimmer - 0.9 mm Rugged design for excellent stability with real-world samples skimmer cone sampler cone
Page 34 Rinse well with de-ionized water DRY THOROUGHLY Reinstall or replace O-rings and reinstall the cones
Ion Extraction to Vacuum Skimmer cone Sampling cone Mach disk Na + Na + Na + Na + + -e Na Ar -e -e + Ar -e + Na Na Ar Ar -e -e - + e Na Ar + Ar Na -e -e Ar + Na -e -e AutoLens ShadowStop Mach disk Plasma Vacuum Vasuum
Elan Series Ion Extraction Process Differential aperture Photon Stop Quadrupole assembly Cylinder lens Skimmer Sampler Page 36
ELAN New Single Ion Lens System New SwiftMount single ion lens with shadow stop Quick-change demountable design Allows removal and replacement of ion lens in less than 3 minutes Reproducible and precise re-positioning of ion lens ever time Shadow Stop
Elan Series Ion Beam Focusing Aperture Cylinder Lens (Net + Charge on Lens) Skimmer Page 38
ELAN DRC AutoLens 1.2 Normalized Signal 1 0.8 0.6 0.4 Li Co Y In Pb U 0.2 1 3 5 7 9 Lens Voltage (V)
Dependence of Optimum Lens Voltage on Analyte Mass 9 8 7 Optimum Lens 6 Voltage 5 4 3 0 50 100 150 200 250 300 Mass, amu Page 40
ELAN DRC Quadrupole Mass Filter Binary gold metallized ceramic rods for hyperbolic quadrupole field. Proven rock-solid mass calibration stability. Rapid scanning characteristics. On-the-fly custom resolution.
Principle of Q-pole Mass Filter + Vcos ωt + + U 2ro Remove lighter mass PB + ( U + Vcos ω t ) PB - ( U + Vcosω t ) -U + Remove heavy mass -Vcosωt
Scanning and Measurement Protocol Sc : scan Stn : settle time Dwn : dwell time low amu high Integration time : Sc x ( Dw1 + Dw2 + +Dwn ) Measurement time : Sc x ((St1 + Dw1 ) + (St2 + Dw2 ) + + (Stn + Dwn ))
ELAN DRC Dual-Stage Discrete Dynode Detector with SimulScan TM
Electron Multiplier Detector To convert ions to electrical signal and detect a number of ions. Amp M + e - e - M + Electron Dynode surface High voltage of EM
Principle of Dual Mode Detector Pulse mode is used for lower concentration. Analog mode is used for higher concentration. Gate closes when signals are too high. Low conc. Amp Discriminator Counter Pulse counting High conc. Gate Amp V/F converter P/A factor Analog counting
ELAN Improvements All new ELANs will have 1 cassette torch mount 3 2 1 One hand removal and replacement 2 3 New lens mount No tools required detector electronics 4 4 Quick release oil drain valves
New cassette torch mount Designed for one hand removal from the instrument Shortcut to install.lnk Ratcheting thumbscrews
New cassette torch mount Unitized design that 1 works with current torch and injectors Automatically makes/breaks gas and electrical connections 2 3 4 Push-on torch gas 3 connectors with o-ringso Ratcheting thumbscrews (like a car gas cap) ensure 4 constant correct torque 2 1 Hybrid between the Optima and current designs
New oil drain valve Quick release valve lever Requires no tools Removable drain hose Kit W101-1013 1013 converts both pumps
ELAN DRC Vacuum System Triple-stage, turbo vacuum system for optimum pumping Roughing pump (25 m 3 /hr) for interface region. Turbo molecular pump (220 L/sec) for Q-pole mass filter chamber. Roughing pump 10 m 3 /hr to back-up turbo molecular pumps.
ELAN DRC Single Ion Lens System SwiftMount single ion lens with shadow stop Quick-change demountable design Allows removal and replacement of ion lens in less than 3 minutes Reproducible and precise repositioning of ion lens ever time Shadow Stop AutoLens
Snap out and Snap in New lens mount Elan photos.exe New Shadow stop sits on posts. Two fingers to remove and replace lens mount. Retrofittable onto existing instruments.