Novel Applications of LA-ICP-MS

Transcription

1 Novel Applications of LA-ICP-MS Dr Ciaran O Connor Laser Ablation Sales Manager Electro Scientific Industries Europe Ltd. New Wave Research Division University of Modena 29 th May

2 Overview What is Laser Ablation? Why use Laser Ablation? Which Wavelength? Current solutions Some Novel Applications 2

3 What is Laser Ablation? Laser Ablation is a solid sampling technique for use with: Inductively coupled plasma mass spectrometry (ICP-MS) Can also be used with Inductively coupled plasma optical emission spectroscopy (ICPOES) A laser is used to generate a fine aerosol of sample particulate A carrier gas (He) is used to transport the particles to the ICP Particles are vaporised and ionised within the plasma Ions are then tranported via electronic or magnetic lenses to a detector where they are counted. Can be used on any solid sample! 3

4 What is Laser Ablation? Hit a sample surface with a high irradiance beam (1µm to 1mm diameter) Laser couples with the sample surface and creates a cloud of particulates Transported to the ICP-MS for detection via a He/Ar carrier stream He in ICP-MS Ablation Cell 4

5 Laser Ablation ICP-MS 5

6 What is Laser Ablation? Expanding plume of ablated material following ablation Short-pulse laser ablation is characterised by a plume of energised particles (visible to the naked eye) Ablation made on silicate glass using UP193SS Careful selection of resonator and homogenising optics gives a flat beam profile capable of depth profiling 6

7 Why use Laser Ablation? Samples can be difficult to digest PGE metals (Pt, Ir, Rh, Os, Pd) Loss of volatiles during digestion Plastics analysis for RoHS (e.g. Hg in PEEK) Quick and efficient sample introduction Easy route from solid to ICP No need for dilution (no loss of sensitivity) Minimising potential for contamination from sample handling High spatial resolution Spot size as low as 1 µm Ideal for spatial chemistry, e.g. zonation in minerals Can also do bulk analysis Breaking through the 1mm barrier High sample quantity for excellent sensitivity Large area for best homogenisation Reduced interferences Oxide interferences removed almost entirely (no water, no acid) Interferences mainly from matrix (polyatomic and isobaric) 7

8 Is Wavelength Important For My Application? What wavelengths are available? 266nm UP266MACRO 4 th Harmonic Solid State Laser (Nd:YAG) 213nm UP213 5 th Harmonic Solid State Laser (Nd:YAG) 193nm UP193FX or UP193SS ArF Excimer (Gas Phase) or pseudo 6 th Harmonic Solid State (Nd:YAG) 8

9 Is Wavelength Important For My Application? Percentage Transmittance NIST610 NIST612 NIST614 NIST nm <1% <1% <1% <1% 213nm <1% <1% <1% 1.5% 266nm <1% <1% 13% 24% 9

10 Is Wavelength Important For My Application? Highly coloured or non-reflective opaque materials can be analysed by all wavelengths (e.g. NIST610) Pale materials required low-uv (<213nm) Transparent and colourless materials require deep-uv (193nm) Fluid Inclusions, Gems, Thin Sections, Geo samples Ceramics, Teeth, Coral, Glasses, Otoliths Tree Rings, Biological Tissues, Plastics, Soils, Air Filters, Metals 266 nm 213 nm 193 nm 10

11 Is Wavelength Important For My Application? Lower wavelength leads to smaller particle size distribution Improved transportation to ICP More fully vaporised and ionised within ICP Higher sensitivity Less Fractionation Fluid Inclusions, Gems, Thin Sections, Geo samples Ceramics, Teeth, Coral, Glasses, Otoliths Tree Rings, Biological Tissues, Plastics, Soils, Air Filters, Metals 266 nm 213 nm 193 nm 11

12 What is Fractionation? Fractionation is a change in the measured ratio of isotopes compared to their true ratio Elemental fractionation is the change in measured relative concentration between different elements (e.g. Cu:Zn, U:Th) Isotopic fractionation is the change in measured relative concentration between isotopes of the same element (e.g. 206 Pb: 208 Pb) Can be caused: At the ablation process During the transport process Within the plasma Fractionation is reduced when the particles size distribution (PSD) is lower Use of lower wavelength (e.g. 193nm) reduces the PSD Use of shorter pulse width reduces the PSD 12

13 Current Solutions...

14 Laser Ablation Family of Products UP193SS UP193FX MIR10 MicroMill UP213 UP193SS UP193FX MACRO Mid-infra-red Precision General Large Deep UV, spot purpose milling in short sizes a laser bench-top pulse tool at UV heating 266nm for excimer a solid bench-top for and sample state laser bulk fusing removal solid laser analysis, ablation state ablation system ultra-trace laser system ablation ICP-MS system and ICP-OES UP213 UP MACRO MIR10 MicroMill 14

15 Some Novel Applications...

16 Forensic Glass Fragment Paint Hair Gun Shot Residue Ink Identification of fakes Drugs Microchips Golf Balls 16

17 Hair Analysis Forensic/Archaeological analysis of hair Toxicological studies Isotope ratio studies Single strand of hair (67µm wide, 25µm hole) Exposure studies (occupational, environmental, anti-terrorism etc.) Can also do growth profiling (scan along length of hair) Also useful for fingernails or biological tissue 9mm line width No fracturing 17

18 Fingerprinting of Paint Depth Profiling Strategy 1: Ablation of a single spot on sample surface Signal changes with depth 18

19 Fingerprinting of Paint Depth Profiling Strategy 2: Line scan on the side profile of paint fragment Steady state signal for each layer 19

20 Glass Analysis Distribution of refractive index (RI) values FBI database of flat glasses, 1964 to 1979 Glitter Standards window Distribution of refractive index (RI) values FBI database of flat glasses, 1980 to 1997 There is less variability in the optical and chemical characteristics of modern glass Traditional techniques such as refractive index discrimination is becoming less effective 20

21 Glass Analysis The major constituents of clear glass are typically very similar Differences may be found at trace levels < 100 µg/g (< 0.01%) 21

22 Glass Analysis A, B,& C Sheet Glass Flat Glass Container Glass Headlamps 22

23 Environmental Air Particulates Soil Plant Tissue Tree Rings 23

24 Atmospheric PM10 Particle Monitoring Monitoring stations set up nationally PM10 particles collected on quartz filters 24

25 Atmospheric PM10 Particle Monitoring Analysis of particulate on filter paper using 266nm Nd:YAG Able to resolve different 9mm line width components of aerosol No fracturing Higher throughput than solution analysis Overcomes selectivity of leaching methods This study used to determine Pb isotopic fingerprint of PM10 particulate across the UK Courtesy of Matt Horstwood, Steve Noble (NIGL, Keyworth) & Steve Smith (ERG, Kings College) 25

26 Atmospheric PM10 Particle Monitoring (projected) 26

27 Atmospheric PM10 Particle Monitoring Comparison with world-wide data 27

28 Soil Pellet Bulk Analysis Pressed powders are known for their heterogeneity Use a laser ablation system with a large beam diameter to average out heterogeneities UP266MACRO 610 micron x 610 micron Scan the beam in a long line to ablate as large an area as possible Element Mean Concentration (ppm) %RSD Certified Concentration (ppm) Cr % 195 Cu % 46.4 Cd % 14.6 Hg % 0.25 Pb %

29 Archaeology & Conservation Ceramics Bone/Teeth Tissue Hair Restoration Ink/Documents 29

30 Art Restoration Must know the composition of materials before restoration Profiling with LA-ICP-MS gives direct information on layer composition Fresco from roof of the Opera House in Ljubljana, Slovenia 30

31 Art Restoration 31

32 Art Restoration 32

33 Biological & Clinical Tissue Analysis Electrophoresis Gels Toxicology 33

34 Imaging of Elements and Proteins in Brain Tissue Multiple line scans combined to create elemental maps 27 Al 24 Mg 57 Fe 66 Zn β-amyloid ( 153 Eu) 63 Cu By labelling proteins with antibodies that have been tagged with Eu it is possible to image a protein distribution by LA-ICP-MS Hutchinson et al. Analytical Biochemistry 346 (2005)

35 Profiling of La-drug Fate in Human Bone Tissue LA-ICP-MS shows elemental distributions in bone samples Facilitates the study of elements in the mineralization zones of bone tissue Resolution shows La occurs only in mineralization zones LA-ICP-MS used to examine how metallo-drug compounds interact with different types of bone tissue to determine the long term fate in the body Acknowledgement A.G. Cox 1, J. Denton 2 and C.W. McLeod 1 1 Centre for Analytical Sciences, University of Sheffield 2 Laboratory Medicine Academic Group, University of Manchesterwww.esi.com 35

36 Oceanographic Corals Fish Scales Otoliths Foraminefera Ocean Geology 36

37 Chronological Exposure to Elements in Fish Otoliths Each day a new layer of biogenic carbonate is formed Each layer is 4µm to 20µm wide Within these layers is locked the environmental chemistry of the fish It is possible to differentiate daily environmental events from the initial larval stages to adulthood 37

38 Chronological Exposure to Elements in Fish Otoliths 38

39 Ablation of Foraminifera Hathorne, E.C. et al, G3, 2003, (4), #

40 Summary of Laser Ablation LA-ICP-MS effective for isotope ratio and elemental analysis at concentration ranges from < 1ppb LA-ICP-OES effective for a concentration range between < 1ppm to %. It is particularly good at handling heavy plasma loading The micro-destructive nature of laser ablation spectrometry preserves sample integrity It is a direct, solid sampling technique Laser Ablation Spectrometry is particular useful when analyzing samples that are difficult to digest or when there is very little of the sample available Laser Ablation Spectrometry is FAST 40