SPI-Dry Sample Preserver Capsule, Small 2.75 in (69.9mm) Diameter x 4.75 in (120.65mm) High
Small Sample Preserver Capsule
Very often it becomes important to save, store, or transport important SEM, TEM, LM or other kinds of samples (e.g. LC "liquid chromatography" standards) under an inert atmosphere. The SPI-Dry Sample Preserver Capsules are designed for purging with an inert gas so that the samples are not necessarily stored under vacuum, but rather they are stored under a positive pressure of the pure inert gas. A vacuum could be used for faster purging by evacuating and then purging and backfilling to a positive pressure. But what distinguishes these Capsules from other storage systems is the ability to store long term under positive pressure.
2.75" (69.9 mm) Diameter x 4.75" (120.65 mm) high
Of course, the SPI-Dry Sample Preserver Capsules could be used as a vacuum storage device but that would not be the best utilization of this product. Specialized containers that enable one to replace the reactive atmospheric air typically present in the container with an inert gas.
Is this kind of elegance really needed for sample storage?
Ask someone doing EBSD and does not want to have a layer of corrosion product on the top of their samples. Or someone who has a chromium coater and is ever so hopeful that they can find some magic device to extend the useful lifetime of their chromium-coated samples. But to some extent, all of the metal coatings used for high resolution SEM applications such as tungsten and iridium will form an oxide layer when exposed to air over time. For the very thin coatings used for this application, any oxide formation is deleterious to the performance of the coating. Previous customers have successfully used the Capsules for storage of samples that would otherwise might react with sulfur in the air (and form sulfides) such as copper or silver.
For a system this size, there is no inexpensive method of producing a vacuum that is sufficiently low enough in the partial pressure of oxygen and water vapor to eliminate the danger to important samples. With the SPI-Dry Sample Preserver Capsules, once under the inert atmosphere, the samples will not undergo reactions such as oxidation, reduction, or corrosion. The entire Sample Preserver Capsule can then be left to sit on one's shelf for extended periods of time or it can be shipped to other laboratories for further analysis. This is because the positive pressure of the inert gas inside the capsule prevents ingress of gaseous species through the container walls and seals.
Who would benefit from the SPI-Dry Sample Preserver Capsules:
Anyone with samples that have been prepared for microscopy, either electron or light, or even surface analysis. We are talking about anyone with samples for which the slightest bit of sample change would be deleterious to the results that one would eventually obtain from the sample. This is the ideal method of storage for standards for microanalysis. And it is the ideal method for transporting important samples from one laboratory to another. It is the consummate way to "save" an important sample.
A simple leak check feature allows for confidence in the quality of the vacuum and/or the inert atmosphere.
Just what can be stored:
Depending on which of the special "racks" have been purchased with the SPI-Dry Sample Preserver Capsule, it is possible to store and/or ship the following:
- Prepared SEM samples on SEM mounts
- Prepared TEM grids stored in specially modified TEM grid storage boxes
- AFM samples mounted on disks
- FIB sample holders
- LC standard samples
- Standards for microanalysis
Cautionary note:One special note about chromium coated SEM samples:
The SPI-Dry™ Sample Preserver Capsules are widely used for the storing of chromium coated samples however this application is becoming less and less important as more and more users realize that osmium metal coated samples are infinitely superior to chromium coated samples.
These capsules are not designed for use under vacuum because plasticizer can come out of the plastic and contaminate certain samples and oxygen could be diffusing in to cause damage to pristine sample surfaces. While the capsules are fabricated to be about as robust as something like this could be, one does have to be careful to not apply too high of a pressure to the capsule when filling with the inert gas. Be sure to follow the instruction manual to avoid over-pressuring the capsule which could result in a catastrophic failure of the capsule.
Two different capsule sizes are available (e.g. "large" and "small") as well as special racks for holding TEM grid storage boxes, difference sizes SEM mounts, and LC standard samples. Be sure you order the appropriate racks for the size capsule(s) purchased. Note that the FIB sample holder rack is presently available only for the large size capsule. The TEM grid box rack comes with three specially vented grid storage boxes for easier purging. Grid boxes hold 50 grids each.
The sample racks are all interchangeable for the appropriate size capsule (small in small, large in large).