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For optimal and economical usage of the existing storage room at -80°C, vessels should be stored in freezer boxes which fit exactly to the vessel dimensions. For sure, 2 mL vessels can be stored in boxes dedicated for 50 mL conical tubes. But this style is uneconomic as you waste a lot of storage space. Besides, removing microtubes out of the 120 mm deep boxes is quite uncomfortable. Nowadays, there are all kind of different box sizes available, fitting to all commonly used vessel types. Different inner grid variants provide a perfect fit to these formats: cryogenic tubes, microtubes, conical tubes 15 and 50 mL, and other laboratory vessels. Common size standard is “inch”, e.g. 2 in boxes for 53 mm microtubes. The footprint of the freezer boxes is by standard 133 mm x 133 mm.
Related metal racks are standardized for these footprints.
The labeling of boxes can be done directly on the surface, via adhesive labels, or via paper slip attached by transparent duct tape. Independent from handwritten, printed labels, or barcodes, a security layer of transparent duct tape might help against mechanical damage.
Printed labels (plain writing or barcode) are recommended to make reading as easy as possible for everyone else besides the author.
Number of samples
At the beginning of a research life, the number of samples resp. vessels is limited. The approach “all protein samples belong to the first box, the DNA samples belong to the second box, ...” fits. Over the time, the accumulation of samples exceeds the capacity of this sorting style.
A sorting system based on metal racks provides a systematic approach. Sample management for easy refinding of samples can be handled by dedicated databases.