Below are some frequently asked questions and answers regarding the Qubit® 2.0 Fluorometer. and Qubit® Fluorometric Quantitation. If you have a question that is not listed below or need additional information, please contact our Technical Support department.

Comparison to UV Absorbance

Q: I already have a Nanodrop® instrument. Why should I use the Qubit® 2.0 Fluorometer?
A: The Nanodrop® instrument uses UV absorbance, which cannot distinguish between DNA, RNA, free nucleotides, and other contaminants.
Q: Why are my UV absorbance readings higher than the Qubit® 2.0 Fluorometer readings?
A: UV absorbance readings measure anything that absorbs at 260 nm, including DNA, RNA, protein, free nucleotides, and excess salt. Qubit® Fluorometric Quantitation only measures the molecule you are interested in, so the number is almost always lower than the A260 reading.
Q: Can the Qubit® 2.0 Fluorometer give an indication of sample quality?
A: Yes. You can use one of the DNA quantitation kits to measure DNA concentration, one of the RNA kits to measure RNA concentration, and the protein kit to measure protein concentration. Use a combination of whichever kits you need for the biomolecule you are interested in and the contaminant of concern. Together, they give you accurate information about how much DNA, RNA, and protein you have in your sample.

General Technical Questions

Q: I already have a Qubit® Fluorometer, is Qubit® 2.0 Fluorometer any different?
A: The Qubit® 2.0 Fluorometer employs a large, robust touch screen for seamless workflow navigation as well as an automatic data logging and a USB port for efficient data management.
Q: Can I use my old Quant-iT™ Kits labeled “for use with Qubit® Fluorometer” with the Qubit® 2.0 Fluorometer?
A: Yes, these kits will work with both the original Qubit® and Qubit® 2.0 Fluorometers.
Q: How many lines of data can the Qubit® 2.0 Fluorometer store?
A: The Qubit® 2.0 Fluorometer can store up to 200 lines of data in a .csv file.
Q: Do I have to use new standards every time?
A: No. But we do recommend using new standards every time you make a new working solution, so that the working solution used in your standards is the same as that used in your samples.
Q: How long can the diluted standards be saved and reused? What if there is evaporation over time (obvious or not obvious)?
A: The diluted standards can be used for up to three hours if using the same working solution for the samples.

Quantitating Protein and Nucleic Acids

Q: Can Qubit® Fluorometric Quantitation quantify plasmids?
A: Yes. Use the Qubit® DNA BR assay for a typical plasmid miniprep with lots of DNA (over 50 ng/μL). Use the Qubit® DNA HS assay for “plasmid rescue” or methods that yield only small amounts of DNA.
Q: Is there a difference in signal between supercoiled and relaxed DNA?
A: Yes. For supercoiled DNA, we recommend nicking the DNA so it is not supercoiled, or using supercoiled DNA as Standard 2.
Q: Does the Qubit® Protein Assay work well in the presence of detergents?
A: It is compatible with very small amounts of detergent. See “Contaminants Tolerated by the Qubit® Protein Assay,” Table 2 on page 6 of the Qubit® Protein Assay Kit product information sheet for specific amounts.

Device Questions

Q: How long does the lamp last? How do I change the lamp?
A: There are two light sources in the Qubit® 2.0 Fluorometer—both are LEDs. They are expected to last at least 5 years.
Q: Can I repair my Qubit® 2.0 Fluorometer?
No. The warranty will be voided if the instrument is disassembled or a customer has attempted to repair the instrument.
Q: What if my Qubit® 2.0 Fluorometer fails under warranty?
A: We will replace your Qubit® 2.0 Fluorometer. Please contact our Technical Support department for details.
Q: What kind of tubes do I need to buy?
A: Use thin-wall, clear 0.5 mL PCR tubes such as Qubit® assay tubes or Axygen PCR-05-C tubes (VWR, part number 10011-830).