Description

Nhs-Fluorescein CAS NO 135795-62-9 is a high-purity, reactive fluorescent labeling reagent, specifically an N-hydroxysuccinimide (NHS) ester derivative of fluorescein. This compound is critical for creating stable, covalent amide bonds with primary amines, enabling the sensitive and specific tagging of proteins, antibodies, peptides, and other biomolecules. It is an essential tool for researchers and manufacturers in bioconjugation, diagnostic assay development, flow cytometry, and fluorescence microscopy, where reliable and bright signal generation is paramount.

Application

• Antibody and Protein Labeling: Covalent conjugation for use in immunoassays (ELISA, Western Blot), immunohistochemistry (IHC), and in vitro diagnostics (IVD).
• Biomolecular Probe Synthesis: Preparation of fluorescent probes for cellular imaging, receptor targeting, and live-cell tracking applications.
• Diagnostic Kit Manufacturing: Key reagent in the production of fluorescent-based diagnostic tests and lateral flow assays.
• Flow Cytometry & FACS: Labeling of cell surface markers, intracellular proteins, or other targets for high-throughput cell analysis and sorting.
• Biomaterials and Polymer Functionalization: Introducing fluorescent tags onto nanoparticles, hydrogels, or other polymeric materials for tracking and characterization.
• Biophysical Studies: Fluorescence Resonance Energy Transfer (FRET) studies and other molecular interaction analyses.

Basic Information

Item	Detail
Product Name	Nhs-Fluorescein
CAS No.	135795-62-9
Molecular Formula	C24H15NO7
Molecular Weight	429.38 g/mol
Synonyms	5(6)-Carboxyfluorescein N-succinimidyl ester; 5(6)-FAM, SE; 6-FAM NHS Ester; Fluorescein-5(6)-isothiocyanate isomer I (common misnomer for NHS ester); 5(6)-Carboxyfluorescein, N-hydroxysuccinimide ester; Succinimidyl ester of fluorescein; FITC-NHS (common abbreviation); Fluorescein NHS ester
EINECS	Contact for details

Quality Control

Our Nhs-Fluorescein is manufactured under strict quality management systems. Each batch undergoes comprehensive analytical testing, including HPLC for purity and identity confirmation, to ensure it meets the stringent requirements for research and diagnostic applications. A detailed Certificate of Analysis (COA) is provided with every shipment, documenting key parameters such as assay purity, solvent content, and functional performance.

Storage

Preserve in a tightly closed container, protected from light. Store at -20°C or below under desiccant. The product is hygroscopic (moisture-sensitive) and light-sensitive. Allow the vial to equilibrate to room temperature in a desiccator before opening to prevent condensation and hydrolysis.

Specification

Item	Specification
Appearance	Orange to red powder
Identification (HPLC/UV)	Conforms to reference standard
Purity (HPLC)	≥ 95.0% (typical >97%)
Solvent Content (Residual DMF/DMSO)	≤ 1.0% (by 1H-NMR)
Water Content (KF)	≤ 1.0%
Functional Performance (Labeling Efficiency)	Conforms to internal standard

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