Laser Ablation 101: An Introduction to LA-ICP-MS Lucas Smith Director of Business Development - Americas Content 66Zn+ E14-17 • 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 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 Sample Analysis Sample Analytical Method Type Requirements SEM/Microprobe Laser Ablation techniques vs GDMS and OES Other XRF Techniques Spark Emission Laser Ablation Non Full coverage Full Turnaround Bulk Spatial Depth Conducting Size/shape Detection limits - conducting 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 ICP-MS Argon Make-Up Helium (or Argon) Sweep Sample He Trigger (Optional) LASER HelEx II Sample Chamber Internal volume (cup) Sample holder Articulated gas inlet/outlet arm • Evolution of Steve Eggins original ANU design S. M. Eggins, L. P. J. Kinsley and J. M. G. Shelley, Appl. Surf. Sci., 1998, 129, 278–286. Typical Lasers used in Laser Ablation Nd:YAG LASER 1064 nm Nd:YAG LASER 2nd 4th Harmonic Harmonic 1064 nm 532 nm 266 nm Nd:YAG LASER 2nd 3rd 5th Harmonic Harmonic Harmonic 1064 nm 532 nm 355 nm 213 nm ArF Excimer LASER Nanosecond pulse width 193 nm Femtosecond lasers Fspulse width Wavelength & Coupling Efficiency • Highly light transmitting materials (e.g. quartz) absorb little light under 300nm • About 20% is absorbed at 266nm • About 50% is absorbed at 213nm 266 • > 90% is absorbed at 193nm FRACTIONATION: When the elemental composition of the material measured at the detector is not representative of the sample’s true composition High Low Particle Size High Particle Size Low PS Distribution High PS Distribution Low Difference in Mass High Difference in Mass Low Difference in Volatility High Difference in Volatility Low 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 Fractionation Laser Type Heating Effects Coupling Typical Particle Overall Efficiency with Size Fractionation Translucent Distribution Effects Samples 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 Very narrow Excellent dependent (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 Application Areas • 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 Trace elemental analysis of stalagmite Zircon Geochronology Chew et al, J. Anal. At. Spectrom., 2017, 32, 262 Agilent 7900 ICP-MS TDY PMI Analyte Excite with HelEx Spot size: 7um Scan speed: 20um/s Rep 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.” Elemental Distribution in Garnet Large (> 5 mm) garnet porphyroblast from medium-grade metamorphic rocks from the South Carpathians (Romania) 48 min Acquisition Time 150Hz Rep Rate • HelEx II & ARIS • Around 30ms transient peaks • ICP-TOF-MS (TOFWERK) 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 • Cobalt Cell & Quad ICP-MS • HDIP Software • 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, 50µm • 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 Amazingly Large Images • Zircon Grain • 3 um spot size @ 250 Hz Zircon from the Ditrau alkaline massif • 4.7 Million Pixel 3D Images (Eastern Carpathians, Romania) • 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 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 Laser Ablation 201: Applications of Laser Ablation & through Collaborative Science Data Reduction Strategies Damon Green – VP of Marketed Technology Dr. Ciprian Stremtan (and Muffin) – Product Specialist .