Leaking centrifuge tubes

Discussions about sample preparation: extraction, cleanup, derivatization, etc.

6 posts Page 1 of 1
Hi,

We use standard disposable polypropylene (PP) 50mL centrifuge tubes with a PP screw-cap for several sample preparation procedures. Everything is well unless there's an organic solvent involved and the tubes have to be shaken in the procedure (think Quechers). In that case, every 5 samples or so there's one leaking which is very annoying. I want to look for an alternative which closes better.

Can anyone recommend similar recipients compatible with organic solvents like acetonitrile, ethyl acetate, (m)ethanol and hexane (at room temperature) which you can close and shake without leaking? Looking at solvent compatibility charts with polymers, I believe PP is still the best choice for this solvent selection?
Probably need to make sure the cap material is also PP, if not that could be the problem instead of the tubes themselves. We have trouble now with some that leak because the ones ordering them went to less expensive brands. The new ones have flat caps, the old ones had harder caps with a concave center that almost never leaked. Sometimes the savings per item is wiped out when you have to redo the samples, but hard to get that through to the bean counters at first.

I am looking at switching our 8270 prep from 1L in continuous liquid liquid extractor to doing 50ml extractions in glass conical centrifuge tubes. These would be the most compatible with organic solvents, but will have to be washed and reused due to cost. I tried that extraction using standard PP tubes and just had too much interference from the release agents on the plastic.

Something like this may work, just have to find the cap that is most compatible with your test.

https://www.fishersci.com/shop/products ... 5/13646108
The past is there to guide us into the future, not to dwell in.
For polypropylene I like Fisherbrand Cat 05-539-9 Non-Sterile 25/bag. I've used them for over 20 years. They have been super clean for me for metals prep and anions (tiny trace of aluminum). They stand up to 20% Nitric 10% Hydrochloric (1X prep) very well but the caps change from blue to white after a few months, but they hold up indefinitely at the nominal 10X dilution. I've never tried them with organic solvents.

For my soil 8015DRO and 8260VOA extractions I use 40mL VOA's. They work fine as long as you don't need really high gravities on your centrifuge. I have IEC Clinical centrifuges. Glass 40mL voas are good for a 5 setting and a 6 if the emuslion won't break; but probably not all the way to 7.
We'd really like to stick to disposable plastic recipients for short sample prep procedures at room temperature. They're clean, light and we're hesitant to increase our dishwashers load - plenty of glassware already.

Since every pesticide lab is doing quechers, there has to be non-leaking plastic recipients resistant to acetonitrile. I'll try to get in touch with suppliers to send us some demo samples.
Rndirk wrote:
We'd really like to stick to disposable plastic recipients for short sample prep procedures at room temperature. They're clean, light and we're hesitant to increase our dishwashers load - plenty of glassware already.

Since every pesticide lab is doing quechers, there has to be non-leaking plastic recipients resistant to acetonitrile. I'll try to get in touch with suppliers to send us some demo samples.


The Fisher part number in the post above sounds like the ones we used, they rarely leaked because of the seal molded into the cap. These new ones with the flat caps, like you get with most Quechers kits, have not been as good.
The past is there to guide us into the future, not to dwell in.
Rndirk wrote:
We'd really like to stick to disposable plastic recipients for short sample prep procedures at room temperature. They're clean, light and we're hesitant to increase our dishwashers load - plenty of glassware already.

Since every pesticide lab is doing quechers, there has to be non-leaking plastic recipients resistant to acetonitrile. I'll try to get in touch with suppliers to send us some demo samples.
You misunderstand, I only use these 40mL VOA vials one time. I use them for the preps I mentioned, and for my 8260 P&T autosampler. At $36 for a box of 72 (their 4-box case price is $144) they cost more than the propylene but I think its worth it to be able to add reagents and spikes through the septums. Septums are silicon with teflon coating facing the inside. I get them from Industrial Glassware.
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