Kovat's retention index

From Wikipedia, the free encyclopedia

Kovat's retention index or simply Kovat's index is a method of quantifying the relative elution times of compounds in gas chromatography in such a way as to help positively identify the components of a mixture. The method takes advantage of the linear relationship between the values of log(tr') and the number of carbon atoms in a molecule. The value of Kovat's index is usually represented by I in mathematical expressions. Its applicability is restricted to organic compounds. The Kovat's index is given by the equation

I = 100 \times \left [ n + ( N - n ) \frac{log (t_{r (unknown)} ') - log (t_{r (n)} ')}{log (t_{r (N)} ') - log (t_{r (n)} ')} \right ]

Where;

I = Kovat's retention index,
n = the number of carbon atoms in the smaller alkane,
N = the number of carbon atoms in the larger alkane,
tr' = the adjusted retention time.

[edit] References