Description

5-Carboxyfluorescein is a highly versatile and reactive derivative of fluorescein, widely used as a key intermediate and fluorescent labeling reagent. Its primary value lies in its carboxylic acid functional group, which enables facile conjugation to biomolecules like proteins, peptides, and nucleic acids via amide bond formation. This compound is essential for researchers and manufacturers in the fields of bioconjugation, diagnostic assay development, and fluorescence microscopy, where it serves as a critical building block for creating sensitive probes and tracers.

Application

• Fluorescent Labeling Reagent: Conjugation to antibodies, proteins, and oligonucleotides for use in immunoassays (ELISA, Western Blot) and fluorescence in situ hybridization (FISH).
• Bioconjugation Intermediate: A key precursor for synthesizing more complex fluorescent probes and dye conjugates with specific targeting properties.
• Cell Tracing and Viability Assays: Used in protocols for tracking cell migration, proliferation, and assessing membrane integrity.
• Diagnostic Kit Manufacturing: Incorporated as an active component in the production of clinical diagnostic kits and biosensors.
• Microscopy and Imaging: Employed as a fluorescent tag in confocal and super-resolution microscopy to visualize cellular structures and processes.
• pH-Sensitive Fluorescent Indicator: Utilized in research applications to measure intracellular pH due to its fluorescence properties being pH-dependent.

Basic Information

Item	Details
Product Name	5-Carboxyfluorescein
CAS No.	76823-03-5
Molecular Formula	C21H12O7
Molecular Weight	376.32 g/mol
Synonyms	5(6)-Carboxyfluorescein; 6-Carboxyfluorescein; 5-CF; Fluorescein 5(6)-carboxylic acid; 3',6'-Dihydroxy-3-oxospiro[isobenzofuran-1(3H),9'-[9H]xanthene]-5-carboxylic acid; 5(6)-Carboxy-3',6'-dihydroxyfluoran; 5(6)-FAM acid
EINECS	Contact for details

Quality Control

Our 5-Carboxyfluorescein is manufactured under strict quality management systems to ensure batch-to-batch consistency and high purity. Each lot undergoes comprehensive analytical testing, including HPLC for purity assessment, spectroscopic identification, and residual solvent analysis. A detailed Certificate of Analysis (COA) documenting all test results is provided with every shipment to support your quality assurance and regulatory compliance needs.

Storage

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

Specification

Item	Specification
Appearance	Orange to red powder
Identification (IR)	Conforms to structure
Purity (HPLC)	≥ 95.0% (typical >97%)
Loss on Drying	≤ 2.0%
Fluorescence Properties	Ex/Em ~492/518 nm (pH 9)

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