4 replies to this topic

[wntiong]

Hi, i need 0.5M EDTA for the microarray work, but ran out of time and money to get one 100ml bottle from market. Found one expired bottle in the lab, expired on 2006 but the color still clear (no yellowish). Just want to know can i use it again? even if i autoclave? what is the risk/what problem it may bring up to affect the microarray result? thanks

[Manoj Agrawal]

I got this information from Sigma website I suppose that -
stock solution of 0.5M EDTA in water (pH 8.5) is stable for months when refrigerated. I am not sure if autoclaving will degrade EDTA.  If you have EDTA in powder form in your lab, you can prepare a stock solution yourself. I have observed that free EDTA acid in water will dissolve only after you put a base like NaOH and also it takes some hours to dissolve

[lab rat]

You can use autoclaved EDTA. The expiry date shouldn't be a problem for most applications, but if you are concerned about the effect on your microarray, buy a new bottle.

[tfitzwater]

I suspect that your old stock is OK, but to make fresh, 500 mM Na2EDTA requires a final concentration of 507 mM NaOH in order to dissolve.

[Dukey]

Just make a new EDTA solution. In the amount of time it took you to post the message and autoclave the old one, you could have made it up. Crazy.

You ran out of money for EDTA????????? Go to another lab and ask someone if you can borrow a few grams, they wont charge you. I think water is free.