Question

"calculate the total mass of DNA that you isolated at the end of Part A"

how would you go about doing this, the concentration in my diluted DNA sample was  6.3ug/ml, and my A60 value was 0.126 Abs i don't know if these numbers help..

part A I had to calculate

the concentration of DNA in my undiluted sample to which I did

Concentration (ug/mL) = (A260 – A280) dilution factor 50ug/mL

C=0.126-0.060 20 50nguL= 66ng/uL

and go that the concentration of DNA in our undiluted sample was 66ng/uL.

Answer 1

The information you provided looks insufficient and the question is quite incomplete. But from the data you provided, following parameters can be inferred-

A260 = 0.126

A280 = 0.060

Not sure if these provided absorbance is for diluted sample or undiluted sample. And pl. elaborate how you arbitrarily took dilution factor as 20.

If the dilution factor is already mentioned in protocol as 20, then your answer is correct. If DF is not mentioned, then the correct method is as follows :

Firstly we need to calculate the dilution factor of diluted sample :

concentration = (A260 - A280) x Dilution Factor x 50 μg/mL

(Reason : An absorbance of 1.0 means the sample contains 50 μg/mL pure dsDNA)

6.3 μg/mL = (0.126-0.060 ) x DF x 50

DF = 6.3 / (0.066 x 50)

= 1.909

Now using this dilution factor, we will calculate the concentration of dsDNA in undiluted sample.

Concentration of undiluted sample = Concentration of Diluted Sample x Dilution Factor

Undiluted concentration = 6.3 x 1.909

= 12.026 μg/mL or 12.026 ng/μL

I've mentioned either of the possibilities of dilution Factor being known and Dilution Factor being unknown respectively. Depending upon the complete question, use either one of them.

Please do leave a thumbs up and an upvote if this answer really helped you :-)