Labeling Dyes


QXL® - Efficient proprietary Quenchers

Quenchers are frequently used in tandem with fluorescent dyes to generate FRET pairs. The most classical FRET pairs are Mca/Dnp and EDANS/DABCYL, both emitting in the blue channel.

Their short absorption wavelengths and low extinction coefficients limit their use as several proteomic samples show background autofluorescence in the blue wavelentgh. QXL® dyes are great choices for you to eliminate these limitations.

Due to the high interest in developing FRET pairs with longer emission wavelengths, AnaSpec has developed the QXL® range of dark quenchers. They are individually optimized to pair with all popular fluorescent dyes such as fluoresceins and rhodamines, as well as our superior HiLyte™ fluor dyes.

Our line of QXL® covers the full visible spectrum with unusually high efficiency.

Our dye/quencher labeling offer

We offer a full-range of dye-quencher FRET pairs and fluorogenic substrates.
The tables below list the dyes and quenchers available to label your custom peptides

FRET Pairs
Dye (donor) Quencher (acceptor) Donor Ex/Em
Mca Dnp

 325/393 nm


 335/493 nm


 492/518 nm


 494/519 nm

HiLyte™ Fluor 488 QXL®520

 502/527 nm

CyLyte Fluor 3 QXL®570

 550/564 nm

HiLyte™ Fluor 532 QXL®570

 545/565 nm

HiLyte™ Fluor 555 QXL®570

 550/566 nm


 541/568 nm

Rox QXL®610

 568/591 nm

CyLyte Fluor 5 QXL®670

 648/663 nm

HiLyte™ Fluor 647 QXL®670

 650/675 nm

CyLyte Fluor 7 IR-QXL®

 750/773 nm

QXL®490, 570, 670 are available as stand-alone catalog products, while our most popular QXL®520 and QXL®610 are exclusively available via our custom labeling services.

  • Fluorescent Dyes

    Standard and proprietary efficient dyes

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  • Detection Reagents

    Kits and Reagents to label peptides and proteins

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