How do you calculate the nitrogen content of a PN solution from protein?

How do you calculate the nitrogen content of a PN solution from protein?

• A. Grams of protein divided by 6.25
• B. Grams of protein multiplied by 6.25
• C. Grams of nitrogen divided by 6.25
• D. Grams of protein divided by 4

Answer: (D)

Protein has about 16% nitrogen by weight, so the nitrogen content is found by dividing the protein amount by 6.25. In other words, grams of nitrogen equals grams of protein divided by 6.25. This 6.25 factor comes from 100 divided by 16 (since 16% is 0.16, and 1/0.16 ≈ 6.25). For example, 80 g of protein contains about 80 ÷ 6.25 = 12.8 g of nitrogen. If you needed to go the other way—protein from nitrogen—you’d multiply the nitrogen grams by 6.25 to get protein grams. Dividing by 4 would imply 25% nitrogen content, which isn’t the standard value for protein.

Protein has about 16% nitrogen by weight, so the nitrogen content is found by dividing the protein amount by 6.25. In other words, grams of nitrogen equals grams of protein divided by 6.25. This 6.25 factor comes from 100 divided by 16 (since 16% is 0.16, and 1/0.16 ≈ 6.25).

For example, 80 g of protein contains about 80 ÷ 6.25 = 12.8 g of nitrogen. If you needed to go the other way—protein from nitrogen—you’d multiply the nitrogen grams by 6.25 to get protein grams.

Dividing by 4 would imply 25% nitrogen content, which isn’t the standard value for protein.