Description

5(6)-Carboxyfluorescein is a high-purity, fluorescent tracer dye and a key intermediate for synthesizing more complex fluorescent probes and labels. This compound is essential for applications requiring sensitive detection and quantification in aqueous and biological systems due to its excellent water solubility and strong fluorescence emission. It is a critical reagent for researchers and manufacturers in the pharmaceutical, biotechnology, diagnostic, and life science research sectors.

Application

• Fluorescent Tracer and Label: Widely used as a fluorescent marker in permeability studies, cell viability assays (e.g., calcein-AM is derived from it), and flow cytometry.
• Diagnostic Reagent Intermediate: Serves as a crucial building block for synthesizing enzyme substrates, fluorescent antibodies, and other diagnostic conjugates.
• Biomolecular Labeling: Used to label peptides, proteins, and oligonucleotides for detection and imaging applications in research.
• Membrane Integrity Assays: Applied in studies of liposome stability, pore formation, and cell membrane permeability.
• pH-Sensitive Fluorescent Dye: Its fluorescence intensity is pH-dependent, making it useful for intracellular pH sensing and related research.
• Capillary Electrophoresis Marker: Acts as a standard or reference compound in separation and analytical techniques.

Basic Information

Product Name	5(6)-Carboxyfluorescein
CAS No.	72088-94-9
Molecular Formula	C21H12O7
Molecular Weight	376.32 g/mol
Synonyms	5(6)-FAM; 5-Carboxyfluorescein; 6-Carboxyfluorescein; 3',6'-Dihydroxy-3-oxospiro[isobenzofuran-1(3H),9'-[9H]xanthene]-5-carboxylic acid; 5(6)-Carboxyfluorescein mixture of isomers; Fluorescein 5(6)-carboxylic acid; 5/6-Carboxyfluorescein; CFDA precursor
EINECS	Contact for details

Quality Control

Our 5(6)-Carboxyfluorescein is produced under strict quality management systems. Each batch undergoes rigorous analytical testing to ensure high purity and consistent performance for sensitive research and manufacturing applications. A comprehensive Certificate of Analysis (COA) detailing purity, identity, and impurity profiles is provided with every shipment.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry place at 15-25°C. The product is hygroscopic (moisture-sensitive); ensure the container is sealed tightly after each use to prevent absorption of atmospheric moisture.

Specification

Item	Specification
Appearance	Orange to red powder
Identification (HPLC/IR)	Conforms to standard
Purity (HPLC)	≥ 95.0% (Total of 5- and 6- isomers)
Water Content (KF)	≤ 5.0 %
Fluorescence	Conforms (Ex/Em ~492/518 nm in buffer)
Solubility	Freely soluble in dilute aqueous base

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