A percentage solution is an amount or volume of chemical or compound per 100 mL of a solution. It is a relative expression of solute to solvent: X amount/100 ml = X%
Percentage solutions are a convenient and easy way to record solution concentrations. An advantage of percentage solutions is that the molecular weight of a compound does not figure into the percentage of the required solution.
There are two types of percentage solutions commonly used in histology:
- Percentage weight by volume (w/v)
- Percentage volume by volume (v/v)
The third type, percentage weight by weight (w/w), is not often used in the histology laboratory and will not be addressed in this course.