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Materials Characterization Labwww.mri.psu.edu/mcl
Elemental Analyses by ICP-AES/ICP-MSHenry Gong, Senior Analytical Chemist
John Kittleson, ICP Mass Spectroscopist
July 27, 2005
Materials Characterization Labwww.mri.psu.edu/mcl
250 MRLAugust 179:45 AMParticle Characterization
114 MRI BldgAugust 249:45 AMX-ray photoelectron spectroscopy (XPS/ESCA)
114 MRI BldgAugust 2411:00 AMAuger Electron Spectroscopy (AES)
541 Deike Bldg.July 279:45 AMChemical analysis (ICP, ICP-MS)
541 Deike Bldg.August 109:45 AMSmall angle x-ray scattering (SAXS)
114 MRI Bldg August 39:45 AMAtomic Force Microscopy (AFM)
250 MRL Bldg.July 209:45 AMOrientation imaging microscopy (OIM/EBSD)
114 MRI BldgJuly 1311:00 AMTEM sample preparation
114 MRI BldgJuly 139:45 AMFocused Ion Beam (FIB)
250 MRL Bldg.July 610:15 AMHigh temperature sintering lab (20 min lecture only)
250 MRL bldg.July 69:45 AMDielectric Characterization (25 min lecture only)
250 MRL Bldg.June 299:45 AMX-ray Diffraction (XRD)
541 Deike Bldg.June 2211:00 AMAnalytical SEM
541 Deike Bldg.June 229:45 AMScanning electron microscopy (SEM)
114 MRI BldgJune 159:45 AMTransmission Electron Microscopy (TEM/STEM)
250 MRL Bldg.June 89:45 AMThermal analysis (TGA, DTA, DSC)
LocationDateTimeTechnique
NOTE LOCATIONS: The MRI Bldg is in the Innovation Park near the Penn Stater Hotel; MRL Bldg. is on Hastings Road.More information: www.mri.psu.edu/mcl
Summer Characterization Open HousesSummer Characterization Open Houses
Materials Characterization Labwww.mri.psu.edu/mcl
BeaverStadium
Park Ave.
Park Ave.
Porter RoadPollock Road
University Drive
College Ave.
Shortlidge Road North
Bur ro w
es Ro ad
00
00
00
00
00
00
00
00
00
Centre Community
Hospital
E&ES Bldg:SEM
Hosler Bldg:SEM, ESEM, FE-SEM, EPMA, ICP, ICP-MS,BET, SAXS
MRI Bldg:XPS/ESCA, SIMS, TEM, HR-TEM, FE-Auger, AFM, XRD
Atherton Street
(322 Business)
MRL Bldg:SEM, XRD, OIM, DTA, DSC, TGA, FTIR, Raman, AFM, Powder, dielectric, prep, shop, IC, UV-Vis
Hastings Road
Penn Stater Hotel
00
Materials Characterization Lab LocationsBldg TelephoneMRL 863-7844MRI 865-0337Hosler 865-1981E&ES 863-4225
Route 322
I-99 00
Steidle Bldg:Nanoindenter
Deike Bldg:
Materials Characterization Labwww.mri.psu.edu/mcl
Outline of ICP-AES segment
― a discussion of ICP-AES principles― various problems encountered in ICP-AES― sample dissolutions― data reduction― some applications― ICP-MS― a brief lab tour after ICP-MS talk
Materials Characterization Labwww.mri.psu.edu/mcl
Emission of the 590 nm wavelength (aka yellow)
Water High Na solution
Materials Characterization Labwww.mri.psu.edu/mcl
Electrons of an atom absorb energy and jump to higher energy levelsWhen they return to normal states, they emit characteristic photons of energyBy isolating these photon wavelengths, we can determine the types and concentrations of the elements present.
ICP-AES – inductively coupled plasma atomic emission spectrophotometry
Concepts, Instrumentation, and Techniques in Inductively Coupled Plasma Optical Emission Spectrometry, Boss and Freeden, Perkin Elmer
Materials Characterization Labwww.mri.psu.edu/mcl
Sample Introduction
• Solution is drawn up by means of a peristaltic pump
• Solution is turned into a fine aerosol by a nebulizer
• Aerosol is introduced into a plasma which excites the atomic species in the aerosol
Materials Characterization Labwww.mri.psu.edu/mcl
Plasma Torch
Materials Characterization Labwww.mri.psu.edu/mcl
Optical Path in Leeman PS3000UV
Materials Characterization Labwww.mri.psu.edu/mcl
Spectrum as dispersed by diffraction grating
Materials Characterization Labwww.mri.psu.edu/mcl
core electrons
Elements by ICP-AES
Materials Characterization Labwww.mri.psu.edu/mcl
Common Problems in ICP-AES
Sampling and Sample Preparation
Spectral Interference
Matrix Effects
Instrumental Drift
Materials Characterization Labwww.mri.psu.edu/mcl
Sampling and Sample Preparation
Are the samples representative of what you are trying to measure?
What steps should MCL take to make your samples representative?
Will any elements volatilize during sample preparation?
How much contamination can the sample tolerate during preparation?
Materials Characterization Labwww.mri.psu.edu/mcl
Spectral Interference
Concepts, Instrumentation, and Techniques in Inductively Coupled Plasma Optical Emission Spectrometry, Boss and Freeden, Perkin Elmer
Some elemental lines may interfere with others.
Best solution is to find another spectral line.
Samples should be scanned for possible problems
Materials Characterization Labwww.mri.psu.edu/mcl
Matrix Effects
Differing viscosities can affect amount of sample uptake
Matrices can change nature of plasma
Certain matrices (HF) can attack torch
Matrices can contain interfering spectral components
Materials Characterization Labwww.mri.psu.edu/mcl
Combined Effects
Concepts, Instrumentation, and Techniques in Inductively Coupled Plasma Optical Emission Spectrometry, Boss and Freeden, Perkin Elmer
Materials Characterization Labwww.mri.psu.edu/mcl
Instrumental Drift
Instrument reading can drift over a period of time due to physical changes in the optical system, or the configuration of the plasma.
Standards need to be run at the beginning and end of each run in order to estimate and correct for this drift.
Materials Characterization Labwww.mri.psu.edu/mcl
Compensation
Standards run with every sample run
Drift Correction taken with every sample run
Matrix of standards should be closely matched with that of the samples
Preliminary scans are taken to see if any spectral overlaps occur
Materials Characterization Labwww.mri.psu.edu/mcl
Basic Analytical Scheme
Concepts, Instrumentation, and Techniques in Inductively
Coupled Plasma Optical Emission Spectrometry, Boss
and Freeden, Perkin Elmer
Materials Characterization Labwww.mri.psu.edu/mcl
Sample Dissolution for Solid Samples
Salt Fusions – typically lithium metaborate and sodium peroxide
Acid Digestions – nitric, hydrochloric, perchloric and hydrofluoric
Microwave Digestion – basically acid digestion in controlled temperature and pressure vessels.
Samples are typically dried, ashed if necessary, and ground to <74 microns prior to dissolution procedures
Materials Characterization Labwww.mri.psu.edu/mcl
Salt Fusion
Sample is mixed with lithium metaborate in a 1:9 ratio
Mix is melted at 900C and dissolved in a nitric acid solution
Pros:
Attacks geologicals and most ceramics
Provides a high concentration salt environment which dampens any intersample matrix differences.
Cons:
Easily volatilized elements cannot be determined
High metal contents may prove difficult
Materials Characterization Labwww.mri.psu.edu/mcl
Graphite crucible with lithium metaborate in furnace
Materials Characterization Labwww.mri.psu.edu/mcl
Acid Digestion
Sample is allowed to dissolve in an acid mix.
Sample is typically heated to speed dissolution.
Pros:
Most direct dissolution, minimizing possible introduction of contaminants
Usually best for metals
Cons:
Ineffective against geologicals and ceramics, especially if Si is to be determined
Can be time consuming
Materials Characterization Labwww.mri.psu.edu/mcl
Acid digestion in a Pt dish
Materials Characterization Labwww.mri.psu.edu/mcl
Microwave Digestion
Sample is allowed under controlled temperature and pressure conditions in a pressure vessel.
Pros:
Effective for a wide range of materials, especially those containing organics
Direct method of dissolution, minimizing introduction of contaminants
Cons:
Time consuming method development
Labor intensive
Materials Characterization Labwww.mri.psu.edu/mcl
MARS 5 Microwave
Digestion System
Materials Characterization Labwww.mri.psu.edu/mcl
Data Reduction
Concepts, Instrumentation, and Techniques in Inductively Coupled Plasma Optical Emission Spectrometry, Boss and Freeden, Perkin Elmer
Materials Characterization Labwww.mri.psu.edu/mcl
What do the data mean?
Precision and accuracy
•Precision is how well the instrument replicates data over time
•Accuracy is how close to the true value the observed results will be
•Precision is generally on the order of 2 to 5 relative weight percent
•Precision will vary from sample type to sample type depending on a number of factors
Materials Characterization Labwww.mri.psu.edu/mcl
Typical Analytical Data
-.01-.0004-.0003-.0004-.0005blank
1.121.1141.1181.1121.11204-1160
.27.272.268.269.27904-1152
2.762.7432.7392.7282.78804-1141
ExtrapolatedMean3rd2nd1stSample
Materials Characterization Labwww.mri.psu.edu/mcl
Typical applications of ICP-AES/ICP-MS
• Natural Waters• Saline Brines• Geological Materials• Ceramics and glasses• Coals and Paper Products
Materials Characterization Labwww.mri.psu.edu/mcl
Natural Waters
•Leaching from mine sites
•Geochemical prospecting
•Sediment analyses
Materials Characterization Labwww.mri.psu.edu/mcl
Discarded candy wrappers Glass and geologicals
More Sample Types
Materials Characterization Labwww.mri.psu.edu/mcl
Strengths of ICP-AES
• Can detect most cations and some anions
• Detection Limits down to parts per trillion for some elements
• Rapid simultaneous determination of selected elements
• Selective determination of other elements in sequential mode
• Good linear range – up to hundreds of ppms for alkalis
• Suitable for routine analyses of multiple samples
• Effective screening tool for ICP-MS samples
Materials Characterization Labwww.mri.psu.edu/mcl
Weaknesses of ICP-AES
• Not effective for low levels of alkalis (less than 1-5 ppm)
• subject to matrix problems
• suitable standards required on every run
• Only elemental data is provided - no direct structural information
• Does not provide, in most cases, parts per billion or parts per trillion data
Materials Characterization Labwww.mri.psu.edu/mcl
MCL capabilities:
Leeman Laboratories PS3000UV for ICP-AES
Lithium Metaborate and Sodium Peroxide Fusion capabilities.
Acid Digestion Facilities
MARS Microwave Digestion Capabilities
Materials Characterization Labwww.mri.psu.edu/mcl
How to get started
3) provide budget and fund number to keep us from getting yelled at.
2b) have one of us perform analysis and data interpretation
2a) attend regular training session OR
1) contact myself, or John Kittleson to discuss your needs
Materials Characterization Labwww.mri.psu.edu/mcl
Acceptable sample forms:
Solutions, preferably aqueous based with minimal or no HFMinimal solution volume is 3-4 ml or more depending on analysesSolids, can usually be dissolved using various techniques
Materials Characterization Labwww.mri.psu.edu/mcl
www.mri.psu.edu/mcl
Henry Gong312 Hosler [email protected]
Materials Characterization Labwww.mri.psu.edu/mcl
Elemental Analyses by High Resolution ICP-MS
John Kittleson317 Holser Building
July 27, 2005
Materials Characterization Labwww.mri.psu.edu/mcl
250 MRLAugust 179:45 AMParticle Characterization
114 MRI BldgAugust 249:45 AMX-ray photoelectron spectroscopy (XPS/ESCA)
114 MRI BldgAugust 2411:00 AMAuger Electron Spectroscopy (AES)
541 Deike Bldg.July 279:45 AMChemical analysis (ICP, ICP-MS)
541 Deike Bldg.August 109:45 AMSmall angle x-ray scattering (SAXS)
114 MRI Bldg August 39:45 AMAtomic Force Microscopy (AFM)
250 MRL Bldg.July 209:45 AMOrientation imaging microscopy (OIM/EBSD)
114 MRI BldgJuly 1311:00 AMTEM sample preparation
114 MRI BldgJuly 139:45 AMFocused Ion Beam (FIB)
250 MRL Bldg.July 610:15 AMHigh temperature sintering lab (20 min lecture only)
250 MRL bldg.July 69:45 AMDielectric Characterization (25 min lecture only)
250 MRL Bldg.June 299:45 AMX-ray Diffraction (XRD)
541 Deike Bldg.June 2211:00 AMAnalytical SEM
541 Deike Bldg.June 229:45 AMScanning electron microscopy (SEM)
114 MRI BldgJune 159:45 AMTransmission Electron Microscopy (TEM/STEM)
250 MRL Bldg.June 89:45 AMThermal analysis (TGA, DTA, DSC)
LocationDateTimeTechnique
NOTE LOCATIONS: The MRI Bldg is in the Innovation Park near the Penn Stater Hotel; MRL Bldg. is on Hastings Road.More information: www.mri.psu.edu/mcl
Summer Characterization Open HousesSummer Characterization Open Houses
Materials Characterization Labwww.mri.psu.edu/mcl
BeaverStadium
Park Ave.
Park Ave.
Porter Roa dPollock Road
University Drive
College Ave.
ShortlidgeR
oad North
Bur ro w
esR
oa d
00
00
00
00
00
00
00
00
00
Centre Community
Hospital
E&ES Bldg:SEM
Hosler Bldg:SEM, ESEM, FE-SEM, EPMA, ICP, ICP-MS,BET, SAXS
MRI Bldg:XPS/ESCA, SIMS, TEM, HR-TEM, FE-Auger, AFM, XRD
Atherton Street
(322 Business)
MRL Bldg:SEM, XRD, OIM, DTA, DSC, TGA, FTIR, Raman, AFM, Powder, dielectric, prep, shop, IC, UV-Vis
Hastings Road
Penn StaterHotel
00
Materials Characterization Lab LocationsBldg TelephoneMRL 863-7844MRI 865-0337Hosler 865-1981E&ES 863-4225
Route 322
I-99 00
Steidle Bldg:Nanoindenter
Deike Bldg:
Materials Characterization Labwww.mri.psu.edu/mcl
Outline
― High Resolution ICP-MS Overview― Challenges ― Applications― Laser Ablation
Materials Characterization Labwww.mri.psu.edu/mcl
• Bulk elemental analysis: Everything in Everything (almost)• Low detection limits• Accurate and precise quantification• Precise isotopic analysis
HR-ICP-MS
The Promise
Materials Characterization Labwww.mri.psu.edu/mcl
Finnigan HR-ICP-MS Element Layout
Materials Characterization Labwww.mri.psu.edu/mcl
Plasma side at 1 atm, back side at ~10-4 mbar
Sampler Cone, ~1mm orifice
Materials Characterization Labwww.mri.psu.edu/mcl
Ions produced by plasma are sampled directly!
Plasma Interface
Materials Characterization Labwww.mri.psu.edu/mcl
Nebulizer and spray chamber attached to torch
Materials Characterization Labwww.mri.psu.edu/mcl
Spectrum
Materials Characterization Labwww.mri.psu.edu/mcl
Ni60
Materials Characterization Labwww.mri.psu.edu/mcl
ICP-MSIDLs
Materials Characterization Labwww.mri.psu.edu/mcl
ICP-MS Challenges
― Spectral Interferences
― Matrix Effects
Materials Characterization Labwww.mri.psu.edu/mcl
Spectral InterferencesFe56 @ 55.93494
Ar40O16 @ 55.95729
Required resolution = ~2,500
Materials Characterization Labwww.mri.psu.edu/mcl
Spectral InterferencesFe56 @ 55.93494
Ar40O16 @ 55.95729
Element using medium resolution
Materials Characterization Labwww.mri.psu.edu/mcl
Spectral InterferencesAs75 @ 74.92160
Ar40Cl35 @ 74.93123
Required resolution = ~7,800
Materials Characterization Labwww.mri.psu.edu/mcl
Spectral InterferencesAs75 @ 74.92160
Ar40Cl35 @ 74.93123
Element using high resolution
Materials Characterization Labwww.mri.psu.edu/mcl
Spectral Interferences
Other methods:
-Mathematical interference corrections, based on isotopic ratios, e.g. Rb87 corrected for Sr87 using Sr88 and natural isotopic abundances.
-Matrix removal, eg hydride generation (for As, Se, Ge) and chromatographic separations.
-Collision/Reaction cells (on quadrupole instruments)
Materials Characterization Labwww.mri.psu.edu/mcl
Matrix effects
― Viscosity effects sample uptake rate. Use internal standard.― Matrix can effect rate of ionization in plasma. Use goodinternal standard― Matrix can contain interfering spectral components. Remove matrix.― Calibration standards must be matrix matched, or calibration performed by standard addition.
Materials Characterization Labwww.mri.psu.edu/mcl
Strengths of High Resolution ICP-MS• Relatively free from spectral interferences• Detection Limits down to parts per quadrillion for some elements• Good linear range (over 9 orders of magnitude)• Rapid determination of many elements• Solid sampling possible via laser ablation
Weaknesses of High Resolution ICP-MS• Expensive, fragile detector (cannot handle concentrations >1ppm)• Cannot handle high total dissolved solids• Somewhat tedious mass calibrations
Materials Characterization Labwww.mri.psu.edu/mcl
Some Applications
• Trace metals in biological media (after dilution)
• Trace metals in drinking water (direct aspiration)
• Wear metals in lubricating oil (via microwave wet ashing)
• Trace metals in soil samples (via microwave wet ashing)
• Trace elements in glass via laser ablation
• Trace metals in native copper fragments via laser ablation
Materials Characterization Labwww.mri.psu.edu/mcl
Wear Metals in Lubricating Oil
Materials Characterization Labwww.mri.psu.edu/mcl
Laser Ablation ICP-MS
Materials Characterization Labwww.mri.psu.edu/mcl
New-Wave Research LUV266X
Materials Characterization Labwww.mri.psu.edu/mcl
Raster pattern on NIST SRM 495
Unalloyed Copper
Materials Characterization Labwww.mri.psu.edu/mcl
• Simplified matrix (reduced spectral interferences)
• Minimal sample preparation
• Very fast (rinse out times ~ seconds) saves $
• Good calibration standards hard to find
• Elemental fractionation
• Qualitative analysis (no standards) is easy
Laser Ablation Highlights
Materials Characterization Labwww.mri.psu.edu/mcl
How to get started
3) Provide budget and fund number!
2) Bring me your samples
1) Contact me to discuss your needs
Materials Characterization Labwww.mri.psu.edu/mcl
Acceptable sample forms:
Aqueous Solutions, dilute HCl, HNO3, HFMinimal solution volume depends on concentrationSolids and slurries, minimum 100mg, depending on digestion method Some solids may be suitable for laser ablation
Rock sectionsMetal fragmentsPressed pelletsAnything that can be glued to a petrographic slide!
Materials Characterization Labwww.mri.psu.edu/mcl
ICP-MS Fees
Instrument time (includes operator) = $90/hrStaff time (sample prep, data workup, digestions, etc) = $30/hrConsultation time to discuss your samples, data, etc is free.
Method development and instrument setup are the most time consuming. Cost per sample goes down with larger sample sets.
Typical ‘Difficult’ analysis – medium or high resolution scans on complex matrices, or refractory samples requiring digestion ~$50/sample
Typical ‘Easy’ analysis – low resolution multielement determination of dilute nitric acid solutions as received ~$15/sample)
Materials Characterization Labwww.mri.psu.edu/mcl
www.mri.psu.edu/mcl
John Kittleson317 Hosler [email protected]