¹H NMR Signal Integration: Overview

Integration or the area under each signal indicates the number of protons contributing to that signal.

For example, in the benzyl acetate spectrum, the area under each peak is shown as a vertical line called an integral, with the integral value listed under it.

Each integral value is divided by the smallest integral value to obtain the ratio of the number of protons producing each signal.

The ratio reveals the relative number of protons and not the absolute number.

Multiplying by two and rounding off gives the actual ratio for benzyl acetate, which is 5:2:3.

Comparing the integration values with the spectrum reveals that the peaks at 7.3, 5.1, and 2 ppm correspond to the five aryl protons, two benzyl protons, and three methyl protons in benzyl acetate, respectively.