Advanced Topic 924 of 1102 Analytical, Lab & Spectroscopy
Integration in NMR
Peak area is proportional to the number of equivalent hydrogens.
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In-depth explanation of Integration in NMR
The integral of an NMR signal, the area under its peak, is proportional to the number of hydrogen nuclei that give rise to it, so the ratio of integrals gives the ratio of equivalent hydrogens. Modern spectrometers measure integrals electronically, and the integral curve displays the relative areas as step heights. The integration gives quantitative information that complements the chemical shift and splitting, which indicate the environment and the neighbours. Integrals must be normalized to a known group to obtain absolute counts, and small components of a mixture can be quantified by comparing with an internal standard. The method is reliable only if the relaxation delay is long enough for all nuclei to recover between pulses.
Going deeper: Integration in NMR
Key ideas: Divide every integral by the smallest to get a whole-number ratio, then scale to match the molecular formula. The ratio gives hydrogens per signal, not per peak in a multiplet. Combined with chemical shift and splitting, each signal is assigned. For a mixture, mole ratio of components equals the ratio of integrals per proton, so percent composition is directly measurable.
Common mistakes and connections: Students forget that integrals are ratios, not absolute counts, and fail to scale to the molecular formula. Mixing up a coupled multiplet with separate signals leads to wrong counts. Exchangeable protons may integrate low. A poor baseline or phasing gives wrong areas. Related to NMR, quantitative analysis and empirical formulas from spectra.
Visualization of Integration in NMR
Signal areas are proportional to the number of equivalent hydrogens, so ethanol integrates 3:2:1 for CH3, CH2 and OH. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Ethanol shows an integral ratio of 3:2:1 for CH3, CH2 and OH.
Frequently asked questions about Integration in NMR
What is Integration in NMR?
Peak area is proportional to the number of equivalent hydrogens.
Is Integration in NMR a beginner, intermediate or advanced topic?
Integration in NMR is a advanced topic in Analytical, Lab & Spectroscopy. It builds on beginner and intermediate topics, so review those first if needed.
What should I learn before Integration in NMR?
Study these earlier topics in Analytical, Lab & Spectroscopy first: NMR Spectroscopy, Chemical Shift, Spin-Spin Splitting.
What comes after Integration in NMR?
The next topics in Analytical, Lab & Spectroscopy are 13C NMR and MRI.
Can I practise Integration in NMR with quizzes?
Yes. The interactive lesson includes a self-check question on Integration in NMR, and the Analytical, Lab & Spectroscopy quiz draws on every topic in this area.
Where Integration in NMR fits in Analytical, Lab & Spectroscopy
Integration in NMR is topic 48 of 99 in Analytical, Lab & Spectroscopy.