QuDye Protein Quantification Kit manual

The kit is used for the quantification of proteins with Qubit™ Fluorometer. QuDye Protein Reagent selectively binds to SDS-protein micelles, so nucleotides, DNA, RNA and other impurities (but not detergents) do not impede the measurements. All reagents are optimized to perform the measurements with Qubit™ fluorometer, the measurement range of initial protein concentrations is 12.5–5000 µg/mL. The assay is highly sensitive and widely applicable due to low fluctuations of fluorescence intensity during quantification of various proteins. The kit includes all the necessary components. Measurements with the kit do not require any special sample preparation (including pre-heating at 95 ºС). All measurements are performed at room temperature and take on average 30 minutes for 5–10 samples.

Kit components

Kit component Count
100 assays
500 assays
15210, QuDye Protein Reagent, 200x, 100 uL 3
55210, QuDye Protein Reagent, 200x, 1.5 mL 1
S1750, QuDye Protein buffer, 1x, 50 mL 1 3
B3650, Protein standard, 0 ng/uL, TE buffer, 1 mL 1 1
B4650, Protein standard, BSA 200 ng/uL in TE buffer, 1 mL 1 1
B5650, Protein standard, BSA 400 ng/uL in TE buffer, 1 mL 1 1

Store at +4 °С. Warm to RT before use.

Shelf life 12 months.

! All measurements with QuDye Protein Quantification Kit should be performed at room temperature (22–28 ºС). Before starting, equilibrate all kit’s solutions to room temperature. Avoid warming the samples, as the sample temperature influences the measurement results; particularly do not hold the assay tubes in your hands just before fluorescence measurement with a Qubit™ fluorometer.


  1. Prepare QuDye Protein dye working solution taking into account that 200 μL of dye working solution will be required for each sample and for each of the three standards. In order to do that, dilute QuDye Protein Reagent concentrate 200‑fold with QuDye Protein buffer.
    For example, to measure 2 samples and 3 standards, prepare 200 μL x 5 = 1000 μL of dye working solution (mix 5 μL of QuDye Protein Reagent concentrate and 995 μL of QuDye Protein buffer).
    ! It is recommended to use dye working solution within several hours after preparation. In case of postponed measurements protect prepared dye working solution from light.
    ! Use only plastic containers to prepare dye working solution, as QuDye Protein Reagent can adsorb to glass surfaces, which results in decreasing of the dye concentration in samples and biases in the measurement results.
  2. Set up three 0.5 ml tubes (thin-walled and optical-transparent) for the standards and one tube for each sample. Label the tube lids. Do not label the side of the tube as this can interfere with the sample read.
  3. Add 190 µL of QuDye Protein dye working solution to each of three tubes used for standards and 10 µL of each Protein standard to the appropriate tube. Vortex for 2–3 seconds and centrifuge briefly.
  4. Add 180–199 µL of QuDye Protein dye working solution to each of the tubes used for samples and 20–1 µL of protein sample, respectively (the total volume should be 200 µL). Vortex for 2–3 seconds and centrifuge briefly.
    The dilution of sample is optional and depends on its initial concentration. The initial sample concentration should be within the range of 12.5–5000 µg/mL for measurement with a Qubit™ fluorometer. At the same time, avoid pipetting small volumes to dilute the initial sample in order to maintain accuracy and precision of your measurements.
  5. Incubate all tubes (containing standards and protein samples) for 15 minutes at room temperature.
  6. Perform the fluorescence measurements.

Fluorescence measurement with a Qubit™ fluorometer

The next steps should be carried out according to the instruction of the Qubit™ fluorometer. Depending on the version of the fluorometer the menu items may differ from the specified below.

  1. On the Home screen of the Qubit™ fluorometer, choose «Quant – It Protein» as the assay type. Press «Go»
  2. With each preparation of the dye working solution, calibrate the fluorometer. Select «Run new calibration» and press «Go».
  3. Insert the tube containing Standard #1 (0 ng/uL, TE buffer) into the sample chamber, close the lid, then press «Go». When the reading is complete (~3 seconds), remove Standard #1.
    Insert the tube containing Standard #2 (BSA 200 ng/uL in TE buffer) into the sample chamber, close the lid, then press «Go». When the reading is complete, remove Standard #2.
    Insert the tube containing Standard #3 (BSA 400 ng/uL in TE buffer) into the sample chamber, close the lid, then press «Go». When the reading is complete, remove Standard #3.
  4. Insert the tube containing user sample into the sample chamber, close the lid, then press «Go». On the screen you will see the QF value.
    Calculate the concentration of the protein sample by the formula: Concentration of the sample = QF value x 200/sample volume.

Related kits

QuDye Protein Quantification Kit (optimized for Qubit®)

Ready kit for simple and tolerant to contaminants quantification of proteins. Kit includes concentrated assay reagent, dilution buffer, and prediluted BSA standards.
Show pricing
Cat. # Quantity Price Lead time
15102 100 assays $59.00 in stock
25102 500 assays $199.00 in stock

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