trFluor™ Eu Acceptor XL665

trFluor™ Eu Acceptor XL665 is an excellent replacement for the commonly used D2 acceptor in labeling antibodies or antigens for bioconjugates paired with europium (Eu)-labeled probes in TR-FRET assays. Eu probes enable time-resolved fluorometry (TRF) in assays requiring high sensitivity. They exhibit large Stokes Shifts and exceptionally long emission half-lives compared to traditional fluorophores such as Alexa Fluor or cyanine dyes. In comparison to other TRF compounds, our TR Fluor™ Eu probes offer high stability, high emission yield, and the ability to be linked to various biomolecules. These probes serve as excellent donors for developing TR-FRET assays in conjunction with trFluor™ Eu Acceptor XL665. Since many biological compounds found in cells, serum, or other biological fluids are naturally fluorescent, using conventional, prompt fluorophores can significantly limit assay sensitivity due to the high background caused by the autofluorescence of the biological molecules to be assayed. Utilizing long-lived fluorophores combined with time-resolved detection, which introduces a delay between excitation and emission detection, minimizes prompt fluorescence interferences.

Protocol

SDS

COA

Catalog	Size	Price	Quantity
1440	1 mg	Price

References

View all 50 references: Citation Explorer

Efficient Eu3+-Integrated UiO-66 Probe for Ratiometric Fluorescence Sensing of Styrene and Cyclohexanone.

Authors:

Zhang, Zhijuan and Liu, Luping and Zhang, Teng and Tang, Hanxiao

Journal:

ACS applied materials & interfaces (2023): 18982-18991

Time-Resolved FRET-Based Immunosensor for the Ultrasensitive and Rapid Detection of Cd2.

Authors:

Han, Zi and Pan, Yi and Chen, Shouhui and Wei, Xinlin

Journal:

Journal of agricultural and food chemistry (2023): 11195-11203

Eu doped Ti3C2 quantum dots to form a ratiometric fluorescence platform for visual and quantitative point-of-care testing of tetracycline derivatives.

Authors:

Fu, Chaojun and Ai, Fanrong and Huang, Jianzhen and Shi, Zhiying and Yan, Xiluan and Zheng, Xiangjuan

Journal:

Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy (2022): 120956

Comparative analysis of lanthanide excited state quenching by electronic energy and electron transfer processes.

Authors:

Parker, David and Fradgley, Jack D and Delbianco, Martina and Starck, Matthieu and Walton, James W and Zwier, Jurriaan M

Journal:

Faraday discussions (2022): 159-174

Monitoring of pesticide amount in fruit and vegetables by a fluorescence-based sensor.

Authors:

Rodrigues, Andreia Cm and Barbieri, Maria Vittoria and Febbraio, Ferdinando

Journal:

EFSA journal. European Food Safety Authority (2022): e200419

Physical properties

Molecular weight	~105000
Solvent	Water (Add 100 µL of H₂O to Cat# 2503 or 1 mL to Cat# 2504 to reconstitute to 10 mg/mL in PBS)

Spectral properties

Excitation (nm)	652
Emission (nm)	659

Storage, safety and handling

H-phrase	H303, H313, H333
Hazard symbol	XN
Intended use	Research Use Only (RUO)
R-phrase	R20, R21, R22
Storage	Refrigerated (2-8 °C); Minimize light exposure

Documents

Protocol
Safety Data Sheet
Certificate of Analysis

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Page updated on October 28, 2025