Thermo Scientific NanoDrop Lite Plus User Manual page 34

1 NanoDrop Lite Plus User Guide
Frequently Asked Questions
34 NanoDrop Lite Plus User Guide
A: No. The Protein A280 application in the NanoDrop Lite Plus is only applicable to
purified proteins. Colorimetric assays such as BCA, Pierce 660 nm, Bradford, and
Lowry are generally used for complex protein samples such as cell lysates and
require a standard curve. If you are currently using a colorimetric assay to measure
proteins, it is recommended that you use one of the preprogrammed colorimetric
methods available on the NanoDrop One/OneC.
Q: Is simply wiping the pedestal surface adequate to prevent sample carryover?
A: Yes. The highly polished quartz stainless steel surfaces of the sample retention
system are resistant to sample adherence. Lint-free lab wipes remove sample very
effectively. However, if a sample is left to dry out on the pedestal, more extensive
cleaning with water is required. See
Q: How do I check the accuracy of the NanoDrop Lite Plus?
A: By using the NanoDrop Performance Verification solution to complete a
performance verification.
Q: Will the sample size affect the concentration results?
A: No. All calculations are volume independent. Sample concentrations for all
applications are calculated using the Beer-Lambert equation, which relates
concentration to absorbance using analyte and wavelength specific extinction
coefficients or conversion factors.
Q: What light pathlengths are used to make measurements and is the user required
to make any calculations relevant to the pathlength?
A: The NanoDrop Lite Plus uses 1.0 mm and 0.2 mm automatically adjusting
pathlenghts and all reported concentration results have taken into account the light
pathlength. The absorbance reported for all measurements is normalized in a 10 mm
pathlength.
Q: What is an appropriate blanking solution?
A: The blanking solution should always be the solvent or buffer used to dissolve the
sample (from the same batch or bottle if at all possible), at the same pH and ionic
strength.
Q: Why do I have negative absorbance values?
A: A blank measurement was made either using a solution with more absorbance
than the sample buffer or on a dirty pedestal. Clean the pedestal and make a new
blank measurement with a fresh aliquot of the appropriate buffer.
Q: How do I keep my sample from spreading on the pedestal?
"Reconditioning" on page 30.
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