Leucocrystal violet 

Leucocrystal violet is a cationic triarylmethane dye. Leucocrystal violet generates a colored purple product in the presence of hydrogen peroxide and horseradish peroxidase, or when oxidized by periodate under the catalysis of horseradish peroxidase. Leucocrystal violet serves as a chromogenic reagent for the determination of submicrogram-level hydrogen peroxide, with no interference from tryptophan, persulfate or chromate. Leucocrystal violet reacts with blood to produce a purple/violet color in the presence of hydrogen peroxide; it forms a very weak fluorophore when acting with whole blood in an unbuffered solution, with a maximum absorption wavelength of 630 nm and a maximum fluorescence emission wavelength of 665 nm upon excitation at 630 nm. Leucocrystal violet is widely used for staining blood residues on porous and non-porous materials^[1][2].

Leucocrystal violet enables a highly sensitive, precise, and selective cell-free colorimetric assay for hydrogen peroxide, with a molar absorptivity of 75,000 M^-1cm^-1 for H₂O₂ detection, stable absorbance readings for at least 4 hours, and minimal interference from tested biological and chemical species^[1].
Leucocrystal violet has a weak UV-Vis absorbance maximum at 590 nm; leucocrystal violet working solution has an absorbance maximum at 630 nm due to low pH-induced protonation of crystal violet impurities; unbuffered whole blood mixed with leucocrystal violet working solution produces a strong UV-Vis absorbance maximum at 630 nm^[2].
Leucocrystal violet (0.6 g Leucocrystal violet in 450 mL deionized water + 9 g 5-sulfosalicylic acid + 45 mL 30% hydrogen peroxide)-treated blood-borne footwear impressions on dark green polypropylene carpet can be effectively enhanced via spectral methods, with optimal results using 400-600 nm excitation, a 695 nm barrier filter, and an integrated CCD IR colour video camera with image integration; maximum fluorescence intensity occurs at 665 nm emission when excited at 630 nm in the absence of substrate interference^[2].

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

373.53

C₂₅H₃₁N₃

603-48-5

Solid

Blue to blue-green

CN(C)C1=CC=C(C(C2=CC=C(N(C)C)C=C2)C3=CC=C(N(C)C)C=C3)C=C1

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]. Horacio A. Mottola, et al. Absorptiometric determination of hydrogen peroxide in submicrogram amounts with leuco crystal violet and peroxidase as catalyst. Anal. Chem. 1970, 42, 3, 410-411.

  [2]. Spence L, et al. Spectral enhancement of leucocrystal violet treated footwear impression evidence in blood. Forensic Sci Int. 2003;132(2):117-124.  [Content Brief]