We have always used N2 purging to dry up the samples. However, since we do not have an automated instrument for the N2 purging, we do it manually, one sample at a time and this is becoming very laborious and time consuming as we have several samples to analyse at a time. Hence, I was thinking of changing my drying procedure and use a SpeedVac Evaporator for the same. Our SpeedVac can be operated at ambient temperatures and I have run some dummy samples and found that the temperature of my sample is actually lower than the ambient temperature because of the vacuum pressure that is generated in the chamber. Hence, I do not think there is a problem of sample heating. My run time was about 1 hour for drying up 1ml sample. I would like to know if this procedure is safe and will it create any problems if I use these samples for GC-MS or LC-MS analysis.
Heating is the one of problems that I would be concerned about, but you have accounted for that already. The other issue would be metabolite volatility but since you can blow dry your sample, it doesn't seem that you have a problem with this either. As a matter of comparison, our protocol for preparing proteomics samples for LC-MS/MS involves drying them by vacuum.
As an alternative, if you have metabolites that are particularly unstable to heat (and not particularly volatile), you could consider freeze-drying?
Go ahead, no problem at all, I'm using speedvac for same being tired of using manual N2 purging. Just check the temp in between, as you have found that it is well below the room temp and I guess there will be no problem with it. Good luck!
Thank you very much for the responses. It has truly built up my confidence.
Dear Deepti,
Hello, I recommend you lyophilisation, lyophilization, or cryodesiccation which is a safe method for drying. But if you encounter with non-volatile and heat stable analytes, your method can be used with confidence. I have an experiment with (some piece of silicon hose, some syringe needle (gauge 19), some glass test tube and a Nitrogen capsule) for drying a set of liquid samples. It as very easy, fast and cheap.
best
mehdi
Thank you very much for the suggestion. We have a lyophilizer, but unfortunately it is used strictly for aqueous solutions and not for organic solvents. My extract will contain methanol hence I cannot use it. The nitrogen capsule assembly seems to be a great setup.
Dear Deepti, For some reasons (e.g. Freeze drying of water insoluble products, Freeze drying of extreme water-unstable products,...) there are some solution for freeze drying organic content solution. If you have pure methanol, using collector chamber -100 C solve your problem, because methanol freeze at -98 C. but fortunately based on methanol eutectic point, in water/methanol solutions you can freeze it at around -80 C. and for second solution, you can change methanol with other organic solvent such as tBA, DMSO, DMF, Acetonitryl,...
Anyway, using nitrogen and needle is very cheap and ease method.
http://www.labconco.com/news/using-methanol-as-an-alternative-to-acetonitrile
best
mehdi
I found your post at research gate while I was looking for information about evaporation of solvents with nitrogen. Me and my colleagues are going to immunoextract Vit D with an Elisa kit from IDS. We dont have any evaporation instrument, and I wonder how you do it manually? Do you need any special equipment? Best regards,
Hi,
You can use your speedvac for lyophilization. Just put (carefully) your frozen samples (-80°C) inside the solvent trap (in my case -120°C).
All the best,
Carlos
Yes, you can but you need to dissolve it in deionized water after drying in speed vac, and then you will need a freeze dryer to evaporate the chemicals completely if any in your samples, u need to repeat this process 2 or 3 times. if there is no chemical added and you have only organic compounds then speed vac drying can work for you.
hello,
I would like to know for metabolomics study by GC-MS in serum sample for drying the sample which method will be good freeze dryer or concentrator.
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