How do you calculate purity on dry basis?

To calculate purity on a dry basis, you first determine the mass of the desired component in the sample and then divide it by the total dry mass of the sample. The result is then multiplied by 100 to express it as a percentage. Ensure that both the desired component and the total mass are measured after removing any moisture content. This calculation provides a clear indication of the concentration of the desired component independent of moisture variations.