To calculate Kovats Index , run a series of C7–C30 saturated n-alkanes for reference and use the following formula to calculate KI:

I=100*[n+(N-n) tʹr(unknown) - tʹr(n) / tʹr(N) - tʹr(n)]

where,

I =Kovats retention index,

n =the number of carbon atoms in the smaller n-alkane,

N=the number of carbon atoms in the larger n-alkane,

tr =the retention time.

Dear Robin, how do I have to prepare the standard solution? Do I have to treat it like my other sample? Or do I have to inject it directly in the GC system? Usally I work with HS-SPME without solvent. Thank you!

You can buy from sigma-aldrich or other suppliers.

Just inject into your gc system using exactly the same chromatographic conditions of your samples.

Remember to change the liner that is different from the one normally used for spme