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Product Line: Life Science

Fluorescein 6-isothiocyanate

CAS 18861-78-4

Molecular structure of Fluorescein 6-isothiocyanate

CAS · 18861-78-4

01

Product Overview

Fluorescein 6-isothiocyanate is a high-purity fluorescein supplied for industrial and specialty chemical applications. Contact our team for specifications, packaging options and lead times.

02

Product Specifications

Appearance: Yellow solid
Identity: HNMR, MS
Purity (HPLC): 95% min
03

Applications

1. Fluorescent Labeling of Biomolecules

Reacts selectively with primary amines on proteins, peptides, and other biomolecules to form stable thiourea linkages.

Used to create fluorescent conjugates for microscopy, flow cytometry, and fluorescence assays.

2. Immunofluorescence and Antibody Labeling

Commonly used to label antibodies and antigens in immunohistochemistry and immunocytochemistry.

The 6-isomer ensures uniform attachment sites, improving signal reliability.

3. Flow Cytometry and FACS

Fluorescein 6-isothiocyanate-labeled molecules are used for cell labeling and sorting, especially in multicolor flow cytometry panels.

4. Fluorescence Microscopy

Suitable for both live-cell and fixed-cell imaging, offering bright green fluorescence and minimal background.

5. Biochemical Assays and Biosensors

Incorporated into enzyme substrates, biosensors, and binding studies to measure activity, affinity, and interaction kinetics.

04

Benefits

1. High Specificity (Single Isomer)

Provides consistent labeling outcomes with fewer positional isomer variations than mixed-isomer FITC.

Critical for quantitative assays and reproducible research.

2. Strong Fluorescent Signal

Emits intense green fluorescence with high quantum yield.

Enables sensitive detection of low-abundance targets.

3. Stable Covalent Bonding

Isothiocyanate group reacts under mild conditions to form durable conjugates, suitable for long-term assays or imaging.

4. Water Solubility and Biocompatibility

Works in aqueous buffers, compatible with biological systems.

Generally low cytotoxicity at standard concentrations.

5. Multiplexing Capability

Can be paired with other fluorophores for multicolor imaging and sorting experiments.

05

Conclusion

Fluorescein 6-isothiocyanate (CAS 18861-78-4) is a highly specific, green-fluorescent labeling reagent designed for covalent attachment to amine-containing biomolecules. As a pure 6-isomer, it offers improved labeling consistency, bright fluorescence, and robust performance in immunofluorescence, flow cytometry, microscopy, and biochemical assays. Its purity and reliable reactivity make it an excellent choice for sensitive and reproducible biological labeling.

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