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Specimen Preparation Tricks of the Trade

Specimen Preparation Tricks of the Trade. Workshop Instructors. Tim Fawcett, International Centre for Diffraction Data Sue Quick, Pennsylvania State University Mark Rodriguez, Sandia National Laboratories Cyrus Crowder, The Dow Chemical Company.

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Specimen Preparation Tricks of the Trade

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  1. Specimen PreparationTricks of the Trade

  2. Workshop Instructors • Tim Fawcett, International Centre for Diffraction Data • Sue Quick, Pennsylvania State University • Mark Rodriguez, Sandia National Laboratories • Cyrus Crowder, The Dow Chemical Company Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company,for the United States Department of Energy under contract DE-AC04-94AL85000.

  3. Tricks of the Trade – A Cast of Thousands !! SUNY X-Ray Clinics 1964-1989 ICDD X-Ray Clinics 1990-Present Denver X-Ray Conference, Every 2-3 Years Ron Jenkins ICDD Members Deane K. Smith DXC, Clinic Participants Robert L. Snyder Vendors Victor E. Buhrke Application Specialists

  4. Dr. Werner Kugler – Forensic Science Laboratory, Germany Dr. David Rendle – The Forensic Science Service, UK Maureen Bottrell – FBI Dr. Jay Riebenspeiss – Texas A&M Bernie Squires – Rigaku-MSC Dr. Martijn Fransen – PANalytical, Netherlands Stephen Williams – PANalytical Dr. Bob He – Bruker-AXS Many Thanks- Recent Contributions!

  5. SpecimenPreparation • Definitions • Sample • material supplied by requestor • Specimen • portion of sample presented to instrument

  6. Goal of Specimen Preparation Prepare a specimen for the diffraction experiment which is representative of the sample to provide the information needed to answer the question posed. Ideally, no more time and effort should be required or expended than is necessary to meet the above goal.

  7. An elaborate procedure is not necessary for phase confirmation Know and understand the question before starting the procedure (assumes that the requestor understands what is really needed) Goal of Specimen Preparation

  8. Every time you prepare a sample • you change it ! • Make sure the sample prep technique • is not destroying, altering or masking the original • problem (tip - analyze before and after preparation steps) • Grinding can destroy soft materials • Binders can mask or dilute phases • - Temperature and humidity can change phase chemistry • Sieving may separate phases as well as separating • particle size

  9. Critical References • “Preparation of Specimens for X-ray Fluorescence and X-Ray Diffraction Analysis”, Victor E. Buhrke, Ron Jenkins, Deane K. Smith (+ 30 friends), Wiley-VCH Publishers,1998 • Selected Resources for X-ray Diffraction, Methods and Practices CD-ROM – “Sample Preparation Methods in X-ray Powder Diffraction” Powder Diffraction, 1, 51 (1986) • “Introduction to X-Ray Powder Diffractometry”, Ron Jenkins, Robert L. Snyder”, Wiley-Interscience Publisher, 1996 • “X-Ray Diffraction Procedures for Polycrystalline and Amorphous Materials”, Harold P. Klug and L. R. Alexander, Wiley-Interscience, 1974 • “X-Ray Diffraction Methods in Polymer Science”, L. R. Alexander, Wiley-Interscience, 1969 (Note: Hard to find), Kreiger Publishing, 1979 (Amazon.com)

  10. Elements of Sample Prep • Basic statistics • Representative samples from bulk • Sampling procedures (macro) • Grinding • Absorption and microabsorption problems • Crystallinity and particle effects • Specimen configuration and equipment geometry • Depth of penetration • Surface roughness • Background, specimen holders • Crystal perfection and extinction • Concentration phases • Slurries and slurry mounts, analyzing films, flowing materials • Use of internal standards • Atmosphere sensitive or toxic materials • Special chemistries (metals, drugs, minerals, thin films, gems, explosives, polymers, nanomaterials) • Temperature and Pressure Studies

  11. Peak Shift 0.05 degrees Sample was so high that it was not in the focusing plane. Container says Plaster of Paris (CaSO4). It looks this stuff has grabbed H2O and CO2 from the air over time Sample holder Thin layer prep CTIMP1a.raw

  12. Specimen Prep – Macro to Micro Courtesy of PANalytical Courtesy FBI

  13. F S S

  14. Macro Riffle Splitters Jaw Crushers Sample Thieves Pulverizer Mills (large) Slicers & Dicers Micro Mortar & Pestle Ball mill (small) Particle Sieve Particle size (microns) Particle Orientation Particle mixing Macro to Micro - Mountains to molehills

  15. Rocklabs Ltd. SPEX SamplePrep, Inc. Chemplex Fernand CLAISSE, Inc. Glen Mills Inc. Mike Handley Analytical Services Spectrum Plus Corporation Scientific Claisse, Inc. Initiative Scientific Products Resources at DXC 2006 !

  16. What is usually going to cause you trouble? Peak Width Intensity - Y-Axis Position - X-Axis (d-spacing)

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