Description

Fluorescein-5-Maleimide is a high-purity, bifunctional labeling reagent that combines the bright green fluorescence of fluorescein with the thiol-specific reactivity of a maleimide group. This compound is critical for creating stable, fluorescent conjugates with proteins, peptides, and other biomolecules containing free sulfhydryl groups. It is an essential tool for researchers and manufacturers in bioconjugation, diagnostic assay development, and fluorescence-based cellular imaging.

Application

• Bioconjugation and Protein Labeling: Site-specific fluorescent labeling of cysteine residues in antibodies, enzymes, and other proteins for diagnostic and therapeutic applications.
• Diagnostic Assay Development: Used as a key component in the production of fluorescent probes and detection reagents for ELISA, lateral flow assays, and other immunoassays.
• Cellular Imaging and Tracking: Labeling of intracellular thiols or engineered cell surface proteins for real-time visualization and tracking in flow cytometry and fluorescence microscopy.
• Biomolecular Interaction Studies: Fluorescent tagging of peptides or small molecules to study binding kinetics, protein-protein interactions, and receptor-ligand dynamics.
• Drug Delivery Research: Conjugation to drug carriers or nanoparticles to monitor distribution, uptake, and release profiles in vitro and in vivo.
• Material Science: Functionalization of surfaces and polymers with fluorescent markers for sensor development and advanced material characterization.

Basic Information

Product Name	Fluorescein-5-Maleimide
CAS No.	75350-46-8
Molecular Formula	C24H13NO7
Molecular Weight	427.37 g/mol
Synonyms	5-Maleimidofluorescein; Fluorescein 5-maleimide; 5-Fluoresceinmaleimide; 5-MF; 6-Maleimido-3',6'-dihydroxy-3H-spiro[isobenzofuran-1,9'-xanthen]-3-one; 3',6'-Dihydroxy-6-maleimido-3H-spiro[isobenzofuran-1,9'-xanthen]-3-one; Fluorescein maleimide; F5M
EINECS	Contact for details

Quality Control

Our Fluorescein-5-Maleimide is manufactured under strict quality management systems. Each batch undergoes comprehensive analytical testing, including HPLC for purity, NMR for structural confirmation, and mass spectrometry to ensure identity and consistency. Certificates of Analysis (COA) with detailed chromatographic data are provided for every shipment, supporting applications in regulated research and development environments.

Storage

Preserve in a tightly closed container, protected from light. Store in a freezer at -20°C or below under desiccated conditions. The product is hygroscopic (moisture-sensitive) and light-sensitive. Allow the vial to equilibrate to room temperature in a dry environment before opening to minimize moisture uptake.

Specification

Item	Specification
Appearance	Orange to red powder
Identification (HPLC)	Conforms
Identification (NMR)	Conforms
Purity (HPLC)	≥ 95.0%
Single Spot (TLC)	Conforms
Extinction Coefficient	~68,000 cm⁻¹M⁻¹ at 494 nm
Water Content (KF)	≤ 2.0%

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.