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QXY21 NHS ester [equivalent to QSY-21 NHS ester]

QXY21 is the same molecule to QSY-21 acid (ThermoFisher). QSY-21 has a broad and intense absorption at ~661 nm maxima with no detectable fluorescence, making it useful as an acceptor in fluorescence resonance energy transfer (FRET) applications. It is a common long-wavelength quencher to best pair with Cy5, Alexa Fluor 647, iFluor 647 or other spectrally similar fluorescent dyes.

Calculators

Common stock solution preparation

Table 1. Volume of DMSO needed to reconstitute specific mass of QXY21 NHS ester [equivalent to QSY-21 NHS ester] to given concentration. Note that volume is only for preparing stock solution. Refer to sample experimental protocol for appropriate experimental/physiological buffers.

0.1 mg0.5 mg1 mg5 mg10 mg
1 mM111.995 µL559.973 µL1.12 mL5.6 mL11.199 mL
5 mM22.399 µL111.995 µL223.989 µL1.12 mL2.24 mL
10 mM11.199 µL55.997 µL111.995 µL559.973 µL1.12 mL

Molarity calculator

Enter any two values (mass, volume, concentration) to calculate the third.

Mass (Calculate)Molecular weightVolume (Calculate)Concentration (Calculate)Moles
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Spectrum

Product family

NameExcitation (nm)Emission (nm)Extinction coefficient (cm -1 M -1)Quantum yieldCorrection Factor (260 nm)Correction Factor (280 nm)
XFD488 NHS Ester *Same Structure to Alexa Fluor™ 488 NHS Ester*499520710000.9210.300.11
XFD350 NHS Ester *Same Structure to Alexa Fluor™ 350 NHS Ester*34344119000-0.250.19
XFD532 NHS Ester *Same Structure to Alexa Fluor™ 532 NHS Ester*534553810000.6110.240.09
XFD594 NHS Ester *Same Structure to Alexa Fluor™ 594 NHS Ester*590618900000.6610.430.56
XFD555 NHS Ester *Same Structure to Alexa Fluor™ 555 NHS Ester*5535681500000.110.080.08
XFD647 NHS Ester *Same Structure to Alexa Fluor™ 647 NHS Ester*6506712390000.3310.000.03
XFD680 NHS Ester *Same Structure to Alexa Fluor™ 680 NHS Ester*6817041840000.3610.000.05
XFD700 NHS Ester *Same Structure to Alexa Fluor™ 700 NHS Ester*6967191920000.2510.000.07
XFD750 NHS Ester *Same Structure to Alexa Fluor™ 750 NHS Ester*7527762400000.1210.000.04
Cy5DIGE NHS ester65167025000010.271, 0.420.020.03
Cy2DIGE NHS ester4925081500000.1200.080.15
Cy3DIGE NHS ester55556915000010.1510.070.073
XFD546 NHS Ester *Same Structure to Alexa Fluor™ 546 NHS Ester*5615721120000.7910.210.12
XFD568 NHS Ester *Same Structure to Alexa Fluor™ 568 NHS Ester*579603913000.6910.450.46
XFD514 NHS Ester *Same Structure to Alexa Fluor™ 514 NHS Ester*51854380000-0.310.18
QXY7 NHS ester [equivalent to QSY-7 NHS ester]--900001--0.22
Cy3B NHS ester56057112000010.5810.0480.069
XFD405 NHS Ester [equivalent to Alexa Fluor™ 405 NHS Ester]40142135,000-0.230.70
CypHer5E NHS Ester643660----
CypHer7E NHS Ester748769----
XFD660 NHS Ester [equivalent to Alexa Fluor® 660 NHS Ester]663691132000-0.000.10
XFD430 NHS ester43254015,000--0.28
Show More (13)

Citations

View all 12 citations: Citation Explorer
A Sensitive Near-Infrared Fluorescent Sensor for Mitochondrial Hydrogen Sulfide
Authors: Ji, A., Fan, Y., Ren, W., Zhang, S., Ai, H. W.
Journal: ACS Sens (2018): 992-997
Imaging intracellular quantum dots: fluorescence microscopy and transmission electron microscopy
Authors: Szymanski, C. J., Yi, H., Liu, J. L., Wright, E. R., Payne, C. K.
Journal: Methods Mol Biol (2013): 21-33
Reversible off-on fluorescence probe for hypoxia and imaging of hypoxia-normoxia cycles in live cells
Authors: Takahashi, S., Piao, W., Matsumura, Y., Komatsu, T., Ueno, T., Terai, T., Kamachi, T., Kohno, M., Nagano, T., Hanaoka, K.
Journal: J Am Chem Soc (2012): 19588-91
Family of enhanced photoacoustic imaging agents for high-sensitivity and multiplexing studies in living mice
Authors: de la Zerda, A., Bodapati, S., Teed, R., May, S. Y., Tabakman, S. M., Liu, Z., Khuri-Yakub, B. T., Chen, X., Dai, H., Gambhir, S. S.
Journal: ACS Nano (2012): 4694-701
Visualizing mechanical tension across membrane receptors with a fluorescent sensor
Authors: Stabley, D. R., Jurchenko, C., Marshall, S. S., Salaita, K. S.
Journal: Nat Methods (2011): 64-7

References

View all 1 references: Citation Explorer
Synthesis and characterization of a small, membrane-permeant, caspase-activatable far-red fluorescent peptide for imaging apoptosis
Authors: Bullok K, Piwnica-Worms D.
Journal: J Med Chem (2005): 5404
Page updated on December 3, 2024

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Physical properties

Molecular weight

892.90

Solvent

DMSO

Spectral properties

Absorbance (nm)

660

Correction Factor (280 nm)

0.32

Extinction coefficient (cm -1 M -1)

890001

Storage, safety and handling

H-phraseH303, H313, H333
Hazard symbolXN
Intended useResearch Use Only (RUO)
R-phraseR20, R21, R22

Storage

Freeze (< -15 °C); Minimize light exposure
UNSPSC12352200
QSY-21 NHS esters (or succinimidyl esters)&nbsp;readily reacts with the primary amines (R-NH<sub>2</sub>) of proteins, amine-modified oligonucleotides, and other amine-containing molecules. The resulting dye conjugates are quite stable.
QSY-21 NHS esters (or succinimidyl esters)&nbsp;readily reacts with the primary amines (R-NH<sub>2</sub>) of proteins, amine-modified oligonucleotides, and other amine-containing molecules. The resulting dye conjugates are quite stable.
QSY-21 NHS esters (or succinimidyl esters)&nbsp;readily reacts with the primary amines (R-NH<sub>2</sub>) of proteins, amine-modified oligonucleotides, and other amine-containing molecules. The resulting dye conjugates are quite stable.
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