Concentration: Formulas

5 or 10% formalin

• Formaldehyde (USP) 100 ml (for 10%) or 50 ml (for 5%)
• Saline solution

0.85% NaCl 900 ml (for 10%) or 950 ml (for 5%)

Note: Formaldehyde is normally purchased as a 37 to 40% HCHO solution; however, for dilution it should be considered to be 100%.

Dilute 100 ml of formaldehyde with 900 ml of 0.85% NaCl solution. (Distilled water may be used instead of saline solution.)