Chem Analysis

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


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


BeaverStadium

Park Ave.

Park Ave.

Porter RoadPollock Road

University Drive

College Ave.

Shortlidge Road North

Bur ro w

es Ro ad

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00

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00

00

00

00

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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:


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


Emission of the 590 nm wavelength (aka yellow)

Water High Na solution


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


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


Plasma Torch


Optical Path in Leeman PS3000UV


Spectrum as dispersed by diffraction grating


core electrons

Elements by ICP-AES


Common Problems in ICP-AES

Sampling and Sample Preparation

Spectral Interference

Matrix Effects

Instrumental Drift


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?


Spectral Interference


Some elemental lines may interfere with others.

Best solution is to find another spectral line.

Samples should be scanned for possible problems


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


Combined Effects



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.


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


Basic Analytical Scheme

Concepts, Instrumentation, and Techniques in Inductively

Coupled Plasma Optical Emission Spectrometry, Boss

and Freeden, Perkin Elmer


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


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


Graphite crucible with lithium metaborate in furnace


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


Acid digestion in a Pt dish


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


MARS 5 Microwave

Digestion System


Data Reduction



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


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


Typical applications of ICP-AES/ICP-MS

• Natural Waters• Saline Brines• Geological Materials• Ceramics and glasses• Coals and Paper Products


Natural Waters

•Leaching from mine sites

•Geochemical prospecting

•Sediment analyses


Discarded candy wrappers Glass and geologicals

More Sample Types


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


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


MCL capabilities:

Leeman Laboratories PS3000UV for ICP-AES

Lithium Metaborate and Sodium Peroxide Fusion capabilities.

Acid Digestion Facilities

MARS Microwave Digestion Capabilities


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


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


www.mri.psu.edu/mcl

Henry Gong312 Hosler [email protected]


Elemental Analyses by High Resolution ICP-MS

John Kittleson317 Holser Building

[email protected]

July 27, 2005


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


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:


Outline

― High Resolution ICP-MS Overview― Challenges ― Applications― Laser Ablation


• Bulk elemental analysis: Everything in Everything (almost)• Low detection limits• Accurate and precise quantification• Precise isotopic analysis

HR-ICP-MS

The Promise


Finnigan HR-ICP-MS Element Layout


Plasma side at 1 atm, back side at ~10-4 mbar

Sampler Cone, ~1mm orifice


Ions produced by plasma are sampled directly!

Plasma Interface


Nebulizer and spray chamber attached to torch


Spectrum


Ni60


ICP-MSIDLs


ICP-MS Challenges

― Spectral Interferences

― Matrix Effects


Spectral InterferencesFe56 @ 55.93494

Ar40O16 @ 55.95729

Required resolution = ~2,500


Spectral InterferencesFe56 @ 55.93494

Ar40O16 @ 55.95729

Element using medium resolution


Spectral InterferencesAs75 @ 74.92160

Ar40Cl35 @ 74.93123

Required resolution = ~7,800


Spectral InterferencesAs75 @ 74.92160

Ar40Cl35 @ 74.93123

Element using high resolution


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)


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.


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


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


Wear Metals in Lubricating Oil


Laser Ablation ICP-MS


New-Wave Research LUV266X


Raster pattern on NIST SRM 495

Unalloyed Copper


• 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


How to get started

3) Provide budget and fund number!

2) Bring me your samples

1) Contact me to discuss your needs


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!


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)


www.mri.psu.edu/mcl

John Kittleson317 Hosler [email protected]