# How can I calculate the percentage of urea in animal feed?

I'am having some doubts in the calculation that concerns the urea percentage in animal feed using the method AOAC $967.07$

How can I calculate the urea percentage using the following data:

The formula is: $\text{Urea %} = \displaystyle\frac{1.0 \times A (\text{test solution}) \times 100}{A \text{ (standard solution})\cdot \text{mg (test portion aliquot)}}$

If ($A$) absorbance of test solution = $0.187$ and its correspondence concentration from calibration curve = $\pu{0.41 mg/5ml}$.

If ($A$) absorbance of standard solution = $0.502$ and its correspondence concentration from calibration curve = $\pu{1.09 mg/5ml}$

Sample is prepared by weighing $\pu{1g}$ in $\pu{500 ml}$.

What can be the urea percentage value?

• I edited the question to make it more readable, did I write the formula correctly? – Berry Holmes May 22 '17 at 6:27
• Thank you , but the formula must be divided by the mg(test portion aliquot) and not multiplied – Nahed May 24 '17 at 9:37
• Oh I'm sorry, I'm editing it again. – Berry Holmes May 24 '17 at 9:40