0
$\begingroup$

I run some algae samples through mass spec a few times over the month to test the P content of algal samples. My (simplified) procedure was as follows:

  1. Put a small portion of algae in a teflon vessel
  2. Add nitric acid and hydrogen peroxide in the teflon vessel
  3. Put that teflon vessel in a microwave digestion system and run it for an hour
  4. Add deionized water to the solution
  5. Put the sample on a hotplate and let it reduce over night.
  6. Add more nitric acid to the solution
  7. Transfer the solution to a 125 ml LDPE bottle
  8. Add deionized water to the solution until it reaches 100 grams

I have decided to run this procedure a few more times so I bought 250 ml LDPE bottles for my experiments and to replace some bottles that I used from another lab. I am not experienced in chemistry at all and a tech has been helping me with these experiments, which I am grateful for. Today I asked the tech how I can clean the bottles to return them to the lab and he told me that those bottles were just thrown away after being used for trace elemental analysis.

I am honestly shocked because they cost like $300 for 30 of these bottles. I need to run over 200 samples and I can't afford to keep replacing these bottles. I have no doubt in the tech's experience and they have been teaching me, but I find it odd that these bottles can't be used again for trace element analysis especially since the teflon and PFA beakers can be reused multiple times and I never heated or reheated these bottles. I simply do not have enough knowledge to understand why I can't soak these bottles in HNO3 for 7 days and call it good? Have any of you tried to clean these bottles after trace elemental analysis?

Thanks!

Improve this question
$\endgroup$
5
  • 1
    $\begingroup$ He's got a point. $\endgroup$
    – Ivan Neretin
    Commented Oct 23, 2023 at 21:19
  • 2
    $\begingroup$ Well, if you were sure they won't affect the measurements... but I guess that would call for special cleaning protocol and testing for elements and adjusting the protocol... which would likely cost much more. $\endgroup$
    – Mithoron
    Commented Oct 23, 2023 at 22:23
  • $\begingroup$ I clean the teflon and the PFA beakers using nitric acid so It seems odd that there is not a protocol for cleaning LDPE after trace element analysis. I mean, I am a beginner so there has to one somewhere right? I don't test if my cleaning of the PFA and the teflon has gone well because I assume there is a tried and true protocol that has already been done many times. $\endgroup$
    – bribina
    Commented Oct 23, 2023 at 22:28
  • $\begingroup$ LDPE is quite different than PFA, perhaps there would be an issue with leftover traces of catalyst used in polymerisation? Wait for some specialist here or ask another IRL. $\endgroup$
    – Mithoron
    Commented Oct 24, 2023 at 23:55
  • $\begingroup$ Apparently, the the lab buys economy LDPE bottles so they cost $2 which is way more cost-efficient than what I bought. I returned the bottles and will be using the economy bottles for the next run. $\endgroup$
    – bribina
    Commented Nov 20, 2023 at 22:45

0

Reset to default

Browse other questions tagged or ask your own question.