Quant-iT™ Protein Assay Kit

Negative fluorescence is a physical impossibility. It is an artifact from software autocorrecting for background signal. This means your reader is picking up and subtracting out background light at the cost of your data. Make sure to do a buffer-only control and assess the type of signal. You may need to switch to a different plate.

Yes, the manual has directions for this application. You will use the 0 ng/µL lambda dsDNA HS standard to generate Standard #1. You will prepare a dilution of the 10 ng/µL lambda dsDNA HS standard to generate Standard #2. You then prepare the samples and compare them to this 2-point standard curve. The Quant-iT dsDNA BR Kit can be used in a similar manner.

The buffer included in the kit should assure the proper pH range, even if your DNA is at a pH outside of this range, since at least a 10-fold excess of kit buffer over sample is used in the assay.

PicoGreen dye and other fluorescence-based quantification reagents are not recommended for quantifying dye-conjugated nucleic acids. The attached dye molecules can interfere with either binding and/or fluorescence output of the quantification reagents.

Strands that are roughly in the 20-mer range or shorter show a lower level of signal. For dsDNA samples that are composed of mostly short strands, the reagent may still be used, but one should use a dsDNA standard that is of comparable length as the sample.

Find additional tips, troubleshooting help, and resources within our Nucleic Acid Quantification Support Center.