Question

In DNA and RNA, nitrogen atom is present in the ring system. Can Kjeldahl method be used for the estimation of nitrogen present in these? Give reasons.

Answer 1

DNA (deoxyribonucleic acid) and RNA (Ribonucleic acid) have nitrogen in the heterocyclic rings.

Nitrogen present in azo groups, rings, and nitro groups cannot be removed as ammonia.

Since, during digestion these compounds does not fully get converted into Ammonium sulphate $(NH_4 )_2 SO_4$

Thus, Kjeldahl method is not suitable to compounds which contain nitrogen in nitro, rings and azo groups and cannot estimate the nitrogen present in DNA and RNA.

Answer 2

Explanation:

DNA and RNA have nitrogen in the heterocyclic rings. Nitrogen present in rings,azo and nitro group's cannot be converted into (NH4)2SO. That's why Kjeldahl method cannot be used for the estimation of nitrogen present in these.