Toluidine Blue Content: 0.15% w/v ± 0.01%.
Malachite Green Content: 0.20% w/v ± 0.01%.
Ethanol Content: 95% v/v ± 2%.
Appearance: Blue-green, homogeneous solution.
Staining Performance: Clearly stains metachromatic granules red-purple.
pH: 4.0-5.0.
Filterability: Passes through filter paper without residue.
Shelf Life: 12 months when stored properly.
Precipitation: No precipitation on standing.
Clarity: Clear solution.
Performance Test: With known C. diphtheriae culture, shows characteristic granules.
