## Calculate the amount of nucleic acid

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LaurieCate
Garter
Posts: 3
Joined: Sat Feb 04, 2006 7:54 pm

### Calculate the amount of nucleic acid

I would be grateful if someone would assist me with the following problem.

Use the following information to solve the question below:
OD x 50 = ug nucleic acid (u stands for micro)

20 ul of an unknown (UK) sample of nucleic acid is added to 980 ul of water and measured in the spectrophotometer. If the OD is 0.40, how much nucleic acid is in 1 ul of UK?

A) So, I plug the Optical Density into the formula:

OD x 50 = 0.40 x 50 = 20 ug nucleic acid

B) I think I need to take into consideration that 980 ul of water was added to the 20 ul of an unknown (UK) sample of nucleic acid. Since, the sample was diluted 50 fold, should I multiply the value found in part A by 50? Will this give me the amount of nucleic acid found in 20 ul of UK?

20 ug nucleic acid x 50 = 1000 ug nucleic acid

C) To find the amount of nucleic acid in 1 ul of UK, do I need to divide the value found in B by 20 ul?

1000 ug nucleic acid / 20 ul = 50 ug/ul

sdekivit
King Cobra
Posts: 586
Joined: Sat Jul 30, 2005 7:16 pm
Location: holland
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you done it all correctly

LaurieCate
Garter
Posts: 3
Joined: Sat Feb 04, 2006 7:54 pm

### Thank you

Thank you for your fast response!

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