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NOTE: Sample preparation is discussed in more detail under Sample Preparation for XRD Analyses in the main XRD Manuals confluence Laboratory Manuals, Guides and Resources>XRD confluence page.
Sample preparations are split into two main categories:
A. Bulk powder samples
B. Clay separations
Before running samples, go over the methods with scientists and check for any special sample requests.
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- With an agate mortar and pestle
- With a Spex shatterbox
- With a Spex mixer mill (tungsten carbide, hardened steel, agate, or alumina ceramic)
- With Retsch MM400 mixer mill (agate)
Mortar and pestle is the most common method for sediment. Below, each method is outlined. Any sample material left in the sample bag remaining once all analyses are complete can be given to the Curator at the end of the expedition to be sent back to the repository. Any sample that has been treated should be disposed of at End of when measurements are completed. However, samples should be kept for a couple weeks after scanning in the XRD as some samples may be scanned again or have multiple treatmentsExpedition, or when all possible rescans and special treatments are completed.
Drying Samples
Freeze-dry sample(s) for at least 12 hours before grinding. If the samples still feel cold when removed from the dryer, the samples still have moisture in them and need to dry longer.
The freeze dryer is comprised of a sample "bell" chamber and a Labconco freeze-dryer. On the bell are two valves, as shown in Figure 5. Each valve has an "Open" and "Closed" position. The top valve controls the vacuum inside of the bell, and the bottom valve controls the air flow between the cooling coil and bell. A valve parallel with the tube is open and allows air flow; a valve perpendicular with the tube is closed. In Figure 5, configuration A (closed) will hold a vacuum, but configuration B (open) will not.
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