Answer posted on June 1, 2018

Dear Alhassan,

[0.5 mg out of 250 g] is [0.5 mg out of 250,000 mg], that is, 0.5/250,000.

Then

0.5/250,000 = 0.000,002 = 0.000,2/100 = 0.000,2 %

With best regards, Jean-Claude

Dear Alhassan Mahama,

Apply the formula % of yield of an isolated compound from plat material

= {(amount of the isolated compound extracted from the material plant) /

(amount of the compound contained in the plant material)} x 100

Note that the unit of the numerator and of the denominator must be same.