Description

5(6)-Carboxynaphthofluorescein is a high-purity, functionalized fluorescein derivative, serving as a critical intermediate for advanced fluorescent probes and labeling reagents. Its core value lies in the carboxylic acid functional group, which enables facile covalent conjugation to biomolecules, nanoparticles, and polymers for sensitive detection and imaging applications. This compound is essential for researchers and manufacturers in the life sciences, diagnostics, and analytical chemistry sectors who require reliable, high-quality fluorescent tags.

Application

• Fluorescent Probe Synthesis: A key precursor for creating custom fluorescent dyes and sensors targeting specific ions or biomolecules.
• Bioconjugation & Labeling: Used to covalently label antibodies, proteins, peptides, and oligonucleotides for fluorescence microscopy (e.g., FLIM, FRET) and flow cytometry.
• Diagnostic Assay Development: Integral in the formulation of enzyme substrates and detection reagents for clinical diagnostics and high-throughput screening (HTS).
• Material Science & Nanotechnology: Functionalization of quantum dots, silica nanoparticles, and polymeric materials to create fluorescent nanocomposites.
• Analytical Chemistry Standards: Serves as a reference standard and calibrant in chromatographic (HPLC) and spectroscopic methods.

Basic Information

Product Name	5(6)-Carboxynaphthofluorescein
CAS No.	128724-35-6
Molecular Formula	C29H16O7
Molecular Weight	476.43 g/mol
Synonyms	5(6)-Carboxy-2',7'-dichloro-3',6'-dihydroxy-3H-spiro[isobenzofuran-1,9'-xanthen]-3-one; 5(6)-Carboxy-2',7'-dichlorofluorescein; Naphthofluorescein-5(6)-carboxylic acid; 2',7'-Dichloro-5(6)-carboxyfluorescein; 5/6-CNF; Dye intermediate for CLIO; Carboxynaphthofluorescein isomer mixture
EINECS	Contact for details

Quality Control

Our 5(6)-Carboxynaphthofluorescein is manufactured under strict quality management systems. Every batch undergoes rigorous analytical testing, including HPLC for purity and identity confirmation, to ensure it meets the high standards required for research and diagnostic applications. A comprehensive Certificate of Analysis (COA) detailing purity, isomer ratio, and impurity profiles is provided with each shipment.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry place at a controlled room temperature (15-25°C). The product is light-sensitive and should be handled under appropriate conditions to prevent degradation.

Specification

Item	Specification
Appearance	Orange to red powder
Identification (HPLC/IR)	Conforms to reference standard
Purity (HPLC, Area %)	≥ 95.0%
Isomer Ratio (5-/6-)	Typically ~1:1 mixture
Loss on Drying	≤ 2.0 %
Heavy Metals (as Pb)	≤ 20 ppm

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