# 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!

-ditaviz-

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.

-ditaviz-

QUOTE (ditaviz @ Dec 15 2008, 05:27 AM)
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.

wouldn't that be 10mg/gm?

-mdfenko-

QUOTE (mdfenko @ Dec 15 2008, 03:54 PM)
QUOTE (ditaviz @ Dec 15 2008, 05:27 AM)
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.

wouldn't that be 10mg/gm?

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

-ditaviz-

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

10mg/mg would be 1000%.

-mdfenko-

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.

-perneseblue-

QUOTE (perneseblue @ Dec 16 2008, 01:38 PM)
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.

couldn't have said it better. thanks!

-ditaviz-

QUOTE (perneseblue @ Dec 16 2008, 01:38 PM)
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.

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

-ditaviz-