NMR Spectra - The Integrator Trace

This page describes how you use an integrator trace (or integration trace) to find the ratio of the numbers of hydrogen atoms in different environments in an organic compound.

What an integrator trace looks like

An integrator trace is a computer generated line which is superimposed on an NMR spectrum. In the diagram, the integrator trace is shown in red.

What an integrator trace shows

An integrator trace measures the relative areas under the various peaks in the spectrum. When the integrator trace crosses a peak or group of peaks, it gains height. The height gained is proportional to the area under the peak or group of peaks.
You measure the height gained at each peak or group of peaks by measuring the distances shown in green in the diagram above - and then find their ratio.

For example, if the heights were 0.7 cm, 1.4 cm and 2.1 cm, the ratio of the peak areas would be 1:2:3.
That in turn shows that the ratio of the hydrogen atoms in the three different environments is 1:2:3.