IRDye® QC-1 NHS Ester

IRDye QC-1 Infrared Dye is the First NonFluorescent Quencher.

IRDye QC-1 is the first non-fluorescent (dark) quencher compatible with a wide range of visible and near-infrared fluorophores (~500-800 nm). It has the widest available quenching range, so you do not need to carefully match the donor's fluorescence spectrum with the acceptor's absorbance. IRDye QC-1 quenches common fluorophores with >97% efficiency1.

IRDye QC-1 stokes shift and wavelength
Energy that is transferred from the donor (Dem) can be emitted at the acceptor's wavelength (Aem), quenching fluorescence.

For more information, see “Spectral Overlap of IRDye QC-1 Absorption with Common Donor Fluorophores” below.

IRDye QC-1 NHS ester can be used for FRET (fluorescence resonance energy transfer) applications such as protease assays. Recently, it has been paired with IRDye 800CW in optoacoustic studies.

IRDye Infrared Dyes Overview

Dye Structure

IRDye QC-1 NHS Ester structure


  • Chemical Formula: C53H62C|N4Na3O16S4
  • Molecular Weight: 1243.75 g/mol
  • Exact Mass: 1242.24

Absorption Spectrum

Solvent Ext. Coeff. (M-1cm-1) Absorption Maxima
1X PBS 96,000 737 nm
Water 98,000 788 nm

Absorption Spectrum in 1X PBS

IRDye® QC-1 Absorption Spectrum in PBS

Absorption Spectrum in Methanol

IRDye® QC-1 Absorption Spectrum in Methanol

Spectral Overlap of IRDye QC-1 Absorption with Common Donor Fluorophores

IRDye QC-1 spectral overlap with common donor fluorophores
Normalized emission spectra for several common donor fluorophores, and the absorption spectrum of IRDye QC-1. All are quenched by IRDye QC-1 with >97% efficiency. Reprinted with permission from Analytical Biochemistry 388 (2009) 220-28.
IRDye QC-1 list of fluorophores
List of fluorophores and spectrally compatible quenchers (shaded box = compatible). Almost all of these common fluorophores are spectrally compatible with IRDye QC-1. No other quencher spans this wide range or is compatible with wavelengths near 800 nm. Reprinted with permission from Analytical Biochemistry 388 (2009) 220-28.


  1. Peng, X et al. A nonfluorescent, broad range quencher dye for Fõrster resonance energy transfer assays. Anal Biochem. 388(2):220-28 (2009).

To discuss purchase quantities over 1 gram or commercial development rights using IRDye infrared dyes, please contact Business Development.

Selected P/N: 929-70030,929-70031



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