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IPTG stability - (Mar/02/2009 )

Hi, sorry if this question sounds stupid, but today I was doing T&A cloning, and by accident I left my 1M IPTG solution outside at room temperature for around 4-5 hours. I was wondering if anyone might know if IPTG outside for this length of time at room temperature would still allow for future use in induction? I typically store it at -20C before and after use, but today was a goof on my part... :rolleyes: Any thoughts would be appreciated. Thanks!


This should be no problem. When doing bulk expressions I often thaw the IPTG whilst I grow the culture to the required OD. This can mean that the IPTG aliquot is at room temp for ca 3 -5 hours. Have never had problems.

It is however good laboratory practice to store reagents in multiple single-use aliquots. This can prevent problems with reagent contamination or degradation.

Hope this helps.