Why it Makes Sense to be Choosy About Your Lab Accessories
Lab tools and accessories are some of the most difficult items to shop for because you have to keep up with differing demands and work within a budget.
Test tube racks are on every benchtop… you shouldn’t have to spend a lot of time thinking about them in order for your ideas to work, and they need to be functional.
That can be easier said than done! And yet at some point, every laboratory has to consider which racks fit the most purposes for the least amount of money.
Perhaps today is your day. This article is here to make things easier for you.
Pictured above, wire test tube rack for 50mL conicals
It’s definitely not rocket science! But we think you’ll be glad you stopped and took some time to scroll through.
Materials and Design Features
Test tube racks come in a variety of sizes, styles, and colors that will fit the more common types of laboratory tubes available.
The materials used should also be evaluated. Wire racks coated with HDPE, Nylon, and polypropylene racks are the most common types to encounter.
Yes, nylon. Now you know it’s not just for pantyhose and nailpolish.
Nylon and HDPE are generally known as less durable plastics than polypropylene and should not be exposed to corrosive chemicals.
Nylon has its own history as a temperature resistant plastic, but polypropylene is the standard.
Polypropylene is the option you’ll want for water bath use because of buoyancy and autoclavability.
If you are more concerned about cost, HDPE coated wire racks and nylon racks are your best friend. These are chemically resistant and durable enough to handle most lab scenarios.
The comparison between nylon and polypropylene is difficult by industry standards, but as far as most biotech and chemistry labs are concerned, polypropylene is the more refined choice.
Every cheap tube rack in an academic lab has survived decades of spills and misuse, take heart!
Nylon vs. Polypropylene Quick Facts
Because it’s such a close call…
Nylon:
- Resistant to gasoline, oils, and most alcohols.
- Has greater tensile strength than polypropylene, but less resistant to cracking under pressure.
- Absorbs some water if submerged.
- Fairly durable and resistant to fungal growth.
- Can be autoclaved and melts at higher temperatures than polypropylene.
- Energy costly to produce, but can be recycled.
- Cheaper than most plastics.
Polypropylene:
- Resistant to most acids and bases. Better chemical resistance than nylon.
- Has slightly less tensile strength than nylon, but it is less prone to cracking under pressure.
- Does not absorb water when submerged.
- Extremely durable, but also biodegradable.
- Can be autoclaved, but has a lower melting point than nylon.
- Sustainable as far as plastics are concerned.
- Not as cheap as nylon and HDPE.
HDPE is less durable than both of these plastics, but it is environmentally conscious and inexpensive, so it’s worth considering if you don’t have concerns about melting or corrosion.
Are My Test Tube Racks Really that Important?
Orientation of Tubes and Sample Quality
A study that mimicked transport of plasma separator tubes looked at baseline levels of several common markers of health found in blood.
The study used eight tubes per group, either lying horizontally or stored in racks and carried within a messenger bag for 30 minutes.
The levels of markers including potassium, lactate dehydrogenase, and sodium were tested post-transport, and it was found that the tubes stored in racks had fewer changes.
Materials and Sample Quality
Another study done on freeze drying rate in a batch of samples used racks made of two different materials to determine whether or not heat transfer was the same between devices.
Although this study looked at polyether ether ketone and polyoxymethylene, it provided evidence that rack materials can influence factors like heat transfer within the samples being held.
The takeaways:
- Storing sample tubes in racks during routine transport can help prevent damage and preserve invaluable resources.
- The materials your racks are made from can and do influence the quality of your work.
Safety Considerations
Your choice of labware should fit neatly into your workspace and use material that is durable. For most settings, these are simple criteria to meet.
Novelty is cool, but keeping it simple will always save you more headaches.
Some important things to think about:
1. How many tubes will you use at once in your most demanding protocol?
A time sensitive process involving many tubes may not be performed safely and efficiently without enough space.
2. What range of sizes do you need to accommodate, and how close of a fit do you need?
If you are working with caustic solutions, vacuum force, or if performing steps in different laboratory locations, you want a close fit.
3. Will you be storing anything long-term in your racks?
Make sure that there is no danger of those containers breaking in their storage environment, especially if freezing.
Bear in mind that freezing, heating, and exposure to different types of chemicals can compromise safe use of a rack.
Make sure you look into chemical and temperature compatibility beforehand.
Selection Tips
The science of science tools… Once you get used to it, it’s second nature.
- Choose racks based on the most frequently used container types in your lab.
- Use one rack for a range of tube sizes. For instance, you can place 5mL and 15mL tubes in the same rack with ease, or 1mL and 1.5mL tubes.
- Do you plan to freeze samples in racks or need to autoclave your racks frequently? Choose polypropylene.
- Does it need to float in water? Polypropylene is generally the best choice for this.
- Just need a lot of racks for as little money as possible? You’ll be able to get away with nylon if your work doesn’t call for harsh extremes.
Versatile Options at Affordable Prices
Stellar Scientific carries all of your traditional laboratory tube racks at affordable prices.
See our selection of plastic and wire racks for standard tubes. Find racks with places for up to 120 15mL conical tubes, and singular stands for larger conicals.
We also have racks for all types of cryovials, PCR tubes, and microcentrifuge racks. Not satisfied? Try our four way devices for all common clinical laboratory tubes.
Specialty Racks and Accessories
Are the usual devices not enough to keep you covered? We carry a number of specialty racks and containers for the lab.
See the Motley Cool all-in-one PCR station and the Adapt-A-Rack multitube rack for benches that crave more convenience.
Take a gander at the polypropylene float racks we carry for unthawing and incubating small samples in water baths, and these portable workstation racks with shopping basket handles.
You may also want to check out the selection of acrylic storage cabinets we have available for enhanced microtube container storage.
Browse Our Online Catalog
From freezer boxes to PCR workstations, we have a variety of solutions for every one of your laboratory setup dilemmas in our online catalog.
Check out our entire test tube rack selection to see all we have to offer, or contact us with questions.
Footnotes:
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Daller, S., Friess, W., & Schroeder, R. (2020). Energy Transfer in Vials Nested in a Rack System During Lyophilization. Pharmaceutics, 12(1), 61. https://doi.org/10.3390/pharmaceutics12010061
SyBridge Technologies. “Polypropylene vs. Nylon (Polyamide): Benefits and Drawbacks for Various Applications.” SyBridge Technologies, 3 Aug. 2023, sybridge.com/polypropylene-vs-nylon-polyamide/.
Wang J, Pyle-Eilola AL. Routine sample transportation of centrifuged barrier tubes impacts certain chemistry analytes. Clin Biochem. 2023 May;115:77-80. doi: 10.1016/j.clinbiochem.2022.08.011. Epub 2022 Sep 2. PMID: 36058286.
“Polypropylene vs. Nylon: Material Differences and Comparisons.” Xometrys RSS, Xometry, 6 Jan. 2023, www.xometry.com/resources/materials/polypropylene...