Description

3',6'-Dihydroxy-6-Isothiocyanatospiro[Isobenzofuran-1(3H),9'-[9H]Xanthen]-3-One is a high-purity, reactive fluorescent dye derivative, widely recognized for its utility as a critical labeling reagent in advanced biochemical research. Its core value lies in its ability to form stable thiourea bonds with primary amines, enabling the sensitive detection and quantification of biomolecules. This compound is essential for researchers and manufacturers in the fields of life sciences, diagnostics, and pharmaceutical development, where precise fluorescent tagging is required for assays, flow cytometry, and immunohistochemistry.

Application

• Fluorescent Labeling Reagent: Primary application for covalent conjugation to proteins, antibodies, peptides, and oligonucleotides via their primary amine groups.
• Bioconjugation & Probe Synthesis: Used in the synthesis of fluorescent probes for cellular imaging, in-situ hybridization (FISH), and receptor binding studies.
• Diagnostic Assay Development: Key component in developing ELISA, western blot, and other immunoassay kits requiring high-sensitivity fluorescence detection.
• Flow Cytometry & Cell Sorting: Employed to label cell surface markers or intracellular targets for analysis and separation in immunology and cancer research.
• Protein & Biomolecule Tracking: Facilitates the study of protein localization, dynamics, and interactions within live or fixed cells.
• Material Science & Sensor Fabrication: Incorporated into polymers or nanomaterials to create fluorescent sensors for chemical or biological detection.

Basic Information

Product Name	3',6'-Dihydroxy-6-Isothiocyanatospiro[Isobenzofuran-1(3H),9'-[9H]Xanthen]-3-One
CAS No.	3326-31-6
Molecular Formula	C21H9NO5S
Molecular Weight	387.37 g/mol
Synonyms	Fluorescein Isothiocyanate Isomer I (FITC I); 5-Isothiocyanatofluorescein; FITC Isomer I; Fluorescein 5-Isothiocyanate; 5-FITC; 3',6'-Dihydroxy-5-isothiocyanatospiro[isobenzofuran-1(3H),9'-[9H]xanthen]-3-one; 5-Fluorescein Isothiocyanate; 5-Isothiocyanato-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthen]-3-one
EINECS	Contact for details

Quality Control

Our 3',6'-Dihydroxy-6-Isothiocyanatospiro[Isobenzofuran-1(3H),9'-[9H]Xanthen]-3-One is manufactured under strict quality management systems. Each batch undergoes rigorous analytical testing, including HPLC for purity and isomer content, spectrophotometry, and functional labeling efficiency tests, to ensure it meets the stringent requirements of research and diagnostic applications. A comprehensive Certificate of Analysis (COA) detailing identity, purity, and performance specifications is provided with every shipment.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry place at 2-8°C (refrigerated). This product is hygroscopic (moisture-sensitive); ensure the container is sealed under inert atmosphere or with desiccant after each use to maintain stability and reactivity. For long-term storage, consider keeping at -20°C under anhydrous conditions.

Specification

Item	Specification
Appearance	Orange to red powder
Identification (IR)	Conforms to structure
Purity (HPLC)	≥ 95.0% (Isomer I)
Absorption Maximum	494 - 498 nm
Emission Maximum	518 - 522 nm
Water Content (KF)	≤ 1.0%
Functional Test (Labeling)	Conforms to reference

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