Reactive Blue 4 

Reactive Blue 4 is an anthraquinone dye used extensively in the textile industry. Reactive Blue 4 is a single colorimetric chemosensor for sequential determination of multiple analytes with different optical responses in aqueous media^[1][2][3].

Reactive Blue 4 (50 μM) can continuously detect copper ions (Cu²⁺), L-arginine (Arg), and L-cysteine ??(Cys) in water (10.0 mM HEPES buffer, pH 7.0). First, the presence of Cu²⁺ causes a color change that is visible to the naked eye, and the spectrum changes according to the binding site-signaling subunit method. Subsequently, the Reactive Blue 4-Cu²⁺ complex was successfully applied to the detection of Cys and Arg through different recognition pathways^[1].
The aqueous solution of Reactive Blue 4 is dark blue, and its UV-Vis spectrum demonstrates an absorption peak at 607 nm. Upon the gradual addition of Cu²⁺ ion to the Reactive Blue 4 solution, a slight red shift from 607 to 619 nm and the gradual decrease in the intensity of absorbance band at 607 nm accompanying with a color change to deep sky blue was observed. Moreover, the existence of an isosbestic point at 645 nm during the titration indicated the formation of a single component^[1].
Reactive Blue 4 is common textile dyes that can be adsorbed onto single-walled carbon nanotubes (SWCNTs) through electrostatic interactions, allowing the separation of residual dyes^[3].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

637.43

C₂₃H₁₄Cl₂N₆O₈S₂

13324-20-4

Solid

Blue to dark blue

O=S(C(C(N)=C1C2=O)=CC(NC3=CC=C(S(=O)(O)=O)C(NC4=NC(Cl)=NC(Cl)=N4)=C3)=C1C(C5=C2C=CC=C5)=O)(O)=O

Room temperature in continental US; may vary elsewhere.

4°C, protect from light

*In solvent : -80°C, 6 months; -20°C, 1 month (protect from light)

* Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month (protect from light). When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.

• [1]. Reactive Blue 4 as a Single Colorimetric Chemosensor for Sequential Determination of Multiple Analytes with Different Optical Responses in Aqueous Media: Cu2+-Cysteine Using a Metal Ion Displacement and Cu2+-Arginine Through the Host-Guest Interaction.  [Content Brief]

  [2]. Chaudhari AU, et al. Effective biotransformation and detoxification of anthraquinone dye reactive blue 4 by using aerobic bacterial granules. Water Res. 2017 Oct 1;122:603-613.  [Content Brief]

  [3]. Machado FM, et al. Adsorption of Reactive Blue 4 dye from water solutions by carbon nanotubes: experiment and theory. Phys Chem Chem Phys. 2012 Aug 21;14(31):11139-53.  [Content Brief]