I'm asking to experienced SPME practitioners how to handle the vials for reuse. It could seem a trivial problem, but working with GC/MS using the wrong detergent to clean septa and vials results in unpredicted mass spectra and problems in quantification.
Yes, chromic acid is good for glass vials. Then dry vials in oven. Then again rinse with dicloromethne or chloroform. then dry.
Gudluck
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Hi for cleaning the SPME vial I use the following procedure. I wash the vials in a normal lab dish washer with a phosphate and aroma free detergent. Then I rinse with acetone and keep the vials in an oven at 280°C until I use them. This keeps the contaminations to a minimum. I work in the area of ultra trace analysis with SPME since decades and have very good results.
BR Erich
I would not use chromic acid because the chromium ions remaining on the glass surface will induce some activities which can cause either a decomposition or adsorption of the analytes causing losses. If you have to clean due to heavy dirt I would recommend the use of Caro´s Acid (this i a mixture of 30% H2O2 and concentrated H2SO4). Must be prepared always fresh in just mL portions must be handled with care!!!!
You can also use Labolene for the cleaning of lab glasswares. You can also use for SPME vials.
To wash the SPME vials first of all keep those vials dipped in chromic acid for overnight. Then wash it by using labolene. After washing with labolene rinsh it with polar, midpolar and nonpolar solvents like methanol,. acetone, hexane etc one by one and keep it in oven for drying. These three type of solvents helps in removing the the impurties of different nature based on polarity.
Sample vials have inert inner glass surface that is likely to be attached by chromic acid, prepared in concentrated sulfuric acid, if kept in contact for longer period such as overnight; and, thus, subsequent chances of adsorption on active surface shall be more pronounced. If at all necessary, use chromic acid in glacial acetic acid. Mind the procedure for waste disposal since hexavalent chromium is toxic.
In my comment please read 'attached' as 'attacked.' Inconvenience regretted.
We soak in a 5% Decon 90 (in deionised water) ("Biodegradable *, phosphate-free, Bactericidal **, non-flammable and totally rinsable") for a couple of hours, rinse thoroughly, rinse in deionised water and leave in over at 120C until next use.
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