• Description

  • Application Data


ECLIPSE™-9 is a generic version and structurally identical to the universally recognised QSY®-9 succinimidyl ester.

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Application Data

Catalogue number crb7008062
λabs 560
Extinction coefficient

85,000 M-1cm-1

Molecular Weight 914.97
Solubility Soluble in DMSO, DMF
Chemistry NHS Ester
Storage -20°C
Manufacturer Product Number 1706
Material Safety Data Sheet (MSDS)

ECLIPSE™-9 is a generic version and structurally identical to the universally recognised QSY®-9 succinimidyl ester.

ECLIPSE™-9 (QSY®-9) succinimidyl ester is a nonfluorescent acceptor dye (Quencher) for preparation of peptide and oligonucleotide FRET probes via aliphatic amine modification. ECLIPSE™-9 is a more hydrophilic version of the ECLIPSE™-7 dark quencher.

With a broad and intense quenching range of 500-600nm reaching a maximum at 560nm it is used as an acceptor for preparation of peptide and oligonucleotide FRET probes.

Cambridge Research Biochemicals has been working with QSY® Quencher (Dark) dyes and the Alexa Fluor® (Bright) dyes since 2001 (20 years) and was granted a non-exclusive licence #3449 back in 2007 to label peptides with the full range of proprietary dyes: Alexa Fluor®, BODIPY®, Oregon Green® and Texas green® fluorophores, enabling CRB to offer one of the most comprehensive custom labelling services available for fluorescent peptides

Since that time Cambridge Research Biochemicals has synthesised many FRET pairs (Dye/Quencher peptides) and mono-labelled peptides with a whole host of fluorescent dyes and quencher pairings from a variety of proprietary dye manufacturers: ThermoFisher scientific (Invitrogen/Molecular Probes), Cytiva (GE), Licor, LGC, Biosearch, Atto-Tec, Cyanagen and in more recent times from generic dye companies: Lumiprobe and Fluoroprobes.

ECLIPSE™-9 (SY-9 NHS Ester) Dark Quencher represents the best generic version of QSY®-9 on the market and provides a real saving to researchers when dual-labelling peptides. All of our generic quenchers are available in larger pack sizes well-suited to the scale of peptide synthesis.

As part of our dye offering we can also provide help and support with peptide strategy, design and labelling. If you would prefer us to label your peptide then we can provide the finished dual-labelled FRET peptide. For labelling enquiries please go to

QSY®-9 succinimidyl ester is a registered trademark and product of ThermoFisher Scientific (formerly Invitrogen® and before that Molecular Probes Inc®). Its patent expired in April 2020 and since then a number of companies have manufactured identical or similar structures negating costly licence and royalty fees associated with proprietary dyes and quenchers.


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