Absorbances for diluted samples
Posted 01 July 2011 - 08:39 AM
Posted 02 July 2011 - 02:20 PM
You should also think about sensitivity of the assay (working range) and possibly other things that can interfere with the assay...
Posted 02 July 2011 - 11:38 PM
A1 = 100ul DNA + 900ul H20
A2 = 100ul from A1 + 900ul H20
A3 = 100ul from A2 +900ul H20
A4 = 10ul DNA + 990ul of H20
A5 = 10ul from A4 + 990ul of H2O
The DNA provided was not really pure. Below is the calculation of dilution factor I have done and the OD260,OD280 and OD260/OD280
** Assuming one A260 unit equals to 60ug of double stranded DNA/ml
Dilution Factor OD 260 OD280 OD260/OD280 Concentration of Stock (OD260 x 50 x Dilution factor)
A1 10, 2.408, 2.659, 0.9058, 1204ug/ml
A2 100, 0.444, 0.307, 1.4452, 2220ug/ml
A3 1000, 0.044, 0.048, 0.9260, 22000ug/ml
A4 100, 0.542, 0.353, 1.5364, 2710ug/ml
A5 1000, 0.008, 0.029, 0.2833, 4000ug/ml
The questions are:
1) How reliable are the absorbances for more dilute sample
2) The tubes in A2 and A4 are of the same dilution factors, why are the concentration different?
Edited by Ic3_88, 03 July 2011 - 09:02 AM.
Posted 03 July 2011 - 04:09 AM
Are you sure you didnt make a typing error there?
Doesn't it need to be 10Ál in 990Ál or?
Edited by pito, 03 July 2011 - 04:09 AM.
Posted 03 July 2011 - 03:46 PM
If you know how the DNA was prepared you can probably even go one step futher and guess what the contaminant is.
Posted 13 July 2011 - 06:36 AM
genius does what it must
i do what i get paid to do