In several cases of spectra recorded at 60MHz, second order effects are observed.  Second order effects cause the N+1 rule to break down and make it harder to directly determine chemical shifts and J-couplings because the coupling patterns become more complex.  Second order effects arise when two nuclei in magnetically different environments are J-coupled and the magnitude of the J-coupling is close to the frequency difference of the chemical shifts.

 Second order effects can be simulated in the NUTS data processing program.  For example, in the test sample provided with all system equipped with the C-13 accessory, n-propylbenzoate demonstrates departure from the first order behavior for the b and c protons (CH2 and CH3, respectively).  The chemical shift for the CH2b is 1.6 and for the CH3c is 0.9, the difference between the two chemical shifts is about 42Hz.  The coupling constant for these two spectra is on the order of 7Hz.  The ratio of J/Ds  is important because it quantifies when second order effects will begin to dominate the spectrum.