CAS No. 193149-74-5

Batch: Purity:99.97
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WST-8 Chemical Structure
Chemical Structure
Check the WST-8 product page for in-depth specifications, including solubility, stock solutions, MOA, and working concentrations.

Chemical Information

IUPAC Name sodium 4-[2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)tetrazol-2-ium-5-yl]benzene-1,3-disulfonate
CAS Number 193149-74-5
Molecular Formula

C20H13N6NaO11S2
Molecular Weight (MW) 600.47
SMILES COC1=C(C=CC(=C1)[N+](=O)[O-])[N+]2=NC(=NN2C3=CC=C(C=C3)[N+](=O)[O-])C4=C(C=C(C=C4)S(=O)(=O)[O-])S(=O)(=O)[O-].[Na+]
InChIKey VSIVTUIKYVGDCX-UHFFFAOYSA-M

Biological Activity

WST-8 is a water-soluble tetrazolium salt utilized as a colorimetric indicator for evaluating cell metabolic activity and cell viability. Cellular dehydrogenases reduce WST-8 to generate a water-soluble formazan dye that absorbs at 460 nm. The amount of generated formazan directly correlates with the number of living cells, enabling the assessment of cell proliferation and cytotoxicity in cell-based assays. [1]

Solubility

Batch:
All in vitro solubility values are batch-tested experimental data (non-literature values).
Solvent Solubility & Note
DMSO 100 mg/mL (166.53 mM)
(Moisture-contaminated DMSO may reduce solubility. Use fresh, anhydrous DMSO. The recommended stock concentration is 10 mM in DMSO.)
Water 100 mg/mL
Ethanol Insoluble
FAQ
Q: Why does a DMSO stock precipitate in media/saline?
A: It is caused by unheated aqueous media (supersaturation), local solvent shock, or incorrect mixing sequence.
How to fix it?
  • Preheat media/saline to 37°C.
  • Mix rapidly (pipette/vortex) upon addition.
  • For complex mixes, always add the aqueous phase last.
  • Re-dissolve minor precipitates with a 37°C water bath and sonication (≤30 min).

Reference

[1] Ishiyama M, et al. Talanta. 1997;44(7):1299-305.

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Note: Technical data last updated: Sep 1, 2026.