Linear Retention Index(LRI)
On the other hand, the peaks of n-alkane appear at even intervals for temperature programming analysis. We call retention index obtained by temperature programming analysis linear retention index (LRI). LRI has advantageous points over retention index when using isothermal analysis. Calculation of retention index is simple, because logarithmic calculation is unnecessary. Additionally, we need not worry about estimating the gas hold-up time. Absolute retention times are sufficient for calculating the retention index.