We tried to compare the absorbance values of several copper sulfate standard solutions using Evolution 220 spectrophotometer (the traditional one), and the Nanodrop, but we we're surprised to find very different values, differing by more than twice. The Nanodrop typically gave higher values for the absorbance. Can anyone explain why this is the case? I thought that Absorbance values should be the same for different spectrophotometers? Because if not, how do you for example rationalize calculating the protein concentration based on absorbance values at 280 nm?
Hello Ms. christine,
Have you found an answer for this question? I am also wondering the same thing as I was measuring the chlorophyll content of rice.
Hi Joana, sorry for the late reply, I think it's the difference in path length for using a cuvette versus using the nanodrop.
Dear All,
I have the same problem with DNA concentrations.
For the same sample of DNA, the quantification with nanodrop 2000 and with spectrophotometer perkin elmer UV/VIS I read very different absorbance.
After calculation of DNA concentration, the DNA read with spectrophotometer has a 151.5 ng/uL concentration, the same DNA read with nanodrop has a concentration of 8 ng/uL.
The nanodrop uses pathlength of 0.5 mm instead 1 cm, but in manual i have read that the software normalizes the concentration (in the final report) with 1 cm pathlength.
I can't explain these differences of concentrations.
If any of you can explain me if i have to correct the concentration of DNA that gave me nanodrop i would be very happy.
thank you
I haven't found an answer to the question but a solution for quantifying chlorophylls in NanoDrop with confidence: https://assets.thermofisher.com/TFS-Assets/MSD/Application-Notes/quantify-chlorophyll-a-and-chlorophyll-b-with-custom-method-T141.pdf
Worked for me!
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- Methodology
- Absorption Spectroscopy
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