Laser Ablation 101:An Introduction to LA-ICP-MS
Lucas SmithDirector of Business Development - Americas
Content• What is laser ablation ICP-MS?• Laser ablation vs other analytical
techniques• Laser sources and selection• The importance of washout times• Fractionation effects• Application examples• Q&A
66Zn+ E14-17
What is Laser Ablation?• A laser ablates a solid sample
& delivers material directly to the ICPMS for elemental analysis
• Eliminates dissolution step and most sample prep
• Maintain spatial resolution
What is Laser Ablation & Why do we care?• Rapid, sensitive multi-element detection at sub-ppm
levels.
• Eliminates (most) labor-intensive sample preparation
• Can sample virtually any material (including liquids)
• Flexible method development
• High spatial resolution of microfeatures
• Sample mapping and depth profiling capabilities
• No contamination of reagents from digestion/dilutions steps
Laser Ablation vs
Other Techniques
Sample AnalysisMethod
SampleType
AnalyticalRequirements
SEM/Microprobetechniques
GDMS and OES
XRF
Spark Emission
Laser AblationBulk
Spatial
Depth
Conducting
Non-conducting
Size/shape
Full coverage
Detection lim
its
Turnaround
What is Laser Ablation ICP-MS?
References: Hu et al, J. Anal. At. Spectrom., 2008, 23 & Eggins et al, Applied Surface Science 127-129 (1998)
Laser Ablation System – Excimer Light Path
Typical Set-Up
Helium (or Argon) SweepArgon Make-Up
Sample
Trigger (Optional)
ICP-MS
LASER
He
HelEx II Sample Chamber
Articulated gas inlet/outlet arm
Sample holder
Internal volume (cup)
S. M. Eggins, L. P. J. Kinsley and J. M. G. Shelley, Appl. Surf. Sci., 1998, 129, 278–286.
• Evolution of Steve Eggins original ANU design
Typical Lasers used in Laser Ablation
Nd:YAG LASER1064 nm
ArF Excimer LASER193 nm
Nd:YAG LASER1064 nm
2ndHarmonic532 nm
4thHarmonic266 nm
Nd:YAG LASER1064 nm
2ndHarmonic532 nm
3rdHarmonic355 nm
5thHarmonic213 nm
Femtosecond lasers
Nan
osec
ond
puls
e w
idth
Fs p
ulse
wid
th
Wavelength & Coupling Efficiency
266
• Highly light transmitting materials (e.g. quartz) absorb little light under 300nm
• About 20% is absorbed at 266nm
• About 50% is absorbed at 213nm
• > 90% is absorbed at 193nm
High Low
Particle Size High
PS Distribution High
Difference in Mass High
Difference in Volatility High
Particle Size Low
PS Distribution Low
Difference in Mass Low
Difference in Volatility Low
FRACTIONATION:When the elemental composition of the material measured at the detector is not representative of the sample’s true composition
Ideal Sample to minimize fractionation:Homogenous, high-density aerosol cloud consisting of small, similarly sized particles.
Fractionation
Liquid Nebulization
Laser Ablation
Reference: D. B. Aeschliman, S. J. Bajic, D. P. Baldwin and R. S. Houk, High-speed digital photographic study of an inductively coupled plasma during laser ablation: comparison of dried solution aerosols from a microconcentric nebulizer and solid particles from laser ablation, J. Anal. At. Spectrom., 2003, 18, 1008–1014
Analytical Implications
Wavelength and FractionationLaser Type Heating Effects Coupling
Efficiency with Translucent
Samples
Typical Particle Size
Distribution
Overall Fractionation
Effects
1064 nm High Very Poor Broad Poor
266 nm Moderate Poor Moderate Moderate
213 nm Low-Moderate Good Narrow Good
193 nm Low Excellent Very narrow Very Good
Femto Very Low Wavelength dependent
Very narrow Excellent (in metallic samples)
What does laser ablation look like?
What Can Be Ablated?• Zircons & a variety of geological samples
• Ice Cores (climatology)
• Paper and ink ablation (forensics)
• Hair Samples (Pb, As & Sr measurement)
• Sunflower leaf
• Metals
• Bio-analysis
Teledyne Laser Portfolio
LSX-213 G2+
Analyte Pharos
Analyte Excite & High Energy Systems
Fusions CO2 & Diode Systems
Iridia – The Evolution of Laser Ablation• Purpose design for high speed imaging
• Dual Attenuation enables stable low energy for bio-imaging applications
• Dual software controlled polarizers for geo-imaging applications
• Cobalt sample chamber for ultimate performance & flexibility
• Earth Sciences • Minerals, toxic elements, zoning, U-Pb dating, coral,
environmental record• Forensics
• Glass, paint, plastic, metals, inks• Archeology
• Ceramics, shards, bone, teeth• Pharmaceutical
• Tablet powders and coatings• Metals
• Alloys, precious metals, QC and defects• General Industrial Materials
• Glass, quartz, silicon• Biological/Medical
• Tissue (frozen or dried), bone, teeth
Application Areas
Trace elemental analysis of stalagmite
Chew et al,J. Anal. At. Spectrom., 2017, 32, 262
Agilent 7900 ICP-MSTDY PMI Analyte Excite with HelExSpot size: 7umScan speed: 20um/sRep Rate: 45Hz
“With an acquisition time of less than 10 minutes per map (which can be decreased even further), there are few reasons to perform spot analyses on complex polyphase zircons other than when sensitivity is needed.”
Zircon Geochronology
Elemental Distribution in Garnet
• HelEx II & ARIS• Around 30ms transient peaks
• ICP-TOF-MS (TOFWERK)
Large (> 5 mm) garnet porphyroblast from medium-grade metamorphic rocks from the
South Carpathians (Romania)
48 min Acquisition Time150Hz Rep Rate
Dr C Stremtan (Teledyne), Dr M Rittner (TOFWERK)
Data interpretation: comparison to histology by overlaying a sequential HE-stained microtome slice
• Evaluation of links between cell-types and the nuclide, compound, or anti-body distribution made possible
Frank Vanhaecke, University of Ghent
3D Fly-Over of Concentration Image
T Van Acker, University of Ghent
Zn in Mouse Small Intestine
50µm
• Deparaffinized 5 µm sections of mouse small intestine villi
• Pixel size of this image is 1 x 1 µm• Total image size 350 x 300 µm, • Spot size 1 µm, • laser rep rate 150 Hz, • energy density 0.44 J cm-2• Pixel acquisition rate 50 pixels/sec
(limited by ICP-MS software)
• 35 minutes to acquire data
• Cobalt Cell & Quad ICP-MS• HDIP Software
Amazingly Large Images • Zircon Grain
• 3 um spot size @ 250 Hz
• 4.7 Million Pixel 3D Images
• 2 hours to acquire on ICP-MS
• Mass: U238
• 7 Minutes acquisition time per layer
• 100 layers acquired
• Single laser shot per pixel
• Z 150 nm material removed
• 1.5 x 1.7 mm
Zircon from the Ditrau alkaline massif (Eastern Carpathians, Romania)
Cobalt – Engineered by Science
Three-Dimensional Reconstruction of the Tissue-Specific Multi-elemental Distribution within Ceriodaphnia dubia via Multimodal Registration Using Laser Ablation ICP-Mass Spectrometry and X-ray Spectroscopic Techniques. Stijn J. M. Van Malderen et Al, DOI: 10.1021/acs.analchem.7b00111
Our laser webinar series continues!
Laser Ablation 102: The Evolution of LA-ICPMS through Collaborative Science
Damon Green – VP of Marketed Technology
Laser Ablation 201: Applications of Laser Ablation & Data Reduction Strategies
Dr. Ciprian Stremtan (and Muffin) – Product Specialist