Concentration of Ethidium Bromide from Fluka (Sigma) - 1%... of what? (Dec/15/2008 )

I'm trying to find out the concentration of our Ethidium Bromide stock... and I'm clueless (not a long history of proper labelling in our lab ). We buy a prepared solution from Sigma, the product number is Fluka 46067. In the specifications it says only 1%. what 1% ? W/V ? That's what I guess, so it would be 10 mg / mL, as usual. I've been trying to get an answer from Sigma, but their contact site refuses to take my message...

Thanks!

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well, I just had an answer from Sigma (I found the phone number! It also works, not all has to be done online...). It is 1% weight/weight, i.e. 10mg/ml.

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wouldn't that be 10mg/gm?

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I guess you mean mg? then it should be about equal, as it is dissolved in H2O... and then 1mg = 1ml

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actually, i mean gm. 1ml of water weighs 1gm.

10mg/mg would be 1000%.

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the density of water is approximately 1 g/cm3 which is also 1g/ml (1cm3 = 1ml)

Thus 1% v/v = 1g EtBr /100g water = 1g EtBr/100ml water = 1% v/w

1g /100ml = 1000mg/100ml = 10mg/ml.

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couldn't have said it better. thanks!

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sorry, this time i got confused with the gm and the mg... hehe

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