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Acclaro Sample Intelligence
Thermo Scientific NanoDrop One User Guide 243
Here is an example of results from a nucleic acid contaminant analysis that contains enough
protein contaminant to affect the measurement results.
1
Based on total sample absorbance (sample plus contaminant)
2
Based on corrected sample absorbance (sample minus contaminant)
Since proteins absorb light near the analysis wavelengths for nucleic acid (230 nm, 260 nm,
and 280 nm), the presence of protein in the nucleic acid sample shown above has pushed the
A260/A280 and A260/A230 ratios out of range and caused the reported nucleic acid
concentration to be higher than the real value. The software identifies the impurity (protein),
and reports the following:
• baseline-corrected absorbance due to protein (2.83) at the analysis wavelength (260 nm)
• % coefficient of variation for the measurement result (uncertainty x 100/measurement
result = 5.3%; a high %CV indicates the measurement result is close to the instrument
detection limit or there is an interfering component)
Protein spectrum
Original nucleic acid spectrum
Corrected nucleic acid spectrum
Out-of-range purity ratios
Original nucleic acid concentration
1
Corrected nucleic acid concentration
2
Protein absorbance
value at 260 nm
% coefficient of variation
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