Formaldehyde (HCOH) is one of the most familiar and effective fixatives. The fixation of the histological specimen material of human or animal origin is commonly performed in a 4% or 10% Formaldehyde solution. Chemically, the 4 % Formaldehyde solution equals a 10 % Formalin solution.

Assay (acidimetric): 36.5 - 38.0 %

Assay (iodometric): 36.5 - 38.0 %

Identity: passes test

Color: ≤ 10 Hazen

Appearance of solution: passes test

Free acid (as HCOOH): ≤ 0.025 %

Density (20 °C): 1.080 - 1.090 g/ml

Chloride (Cl): ≤ 0.0001 %

Sulfate (SO₄): ≤ 0.002 %

Heavy metals (as Pb): ≤ 0.0002 %

Fe (Iron): ≤ 0.0001 %

Methanol (GC): 9.0 - 11.0 %

Sulfated ash: ≤ 0.002 %