#""^13"C"# NMR spectroscopy was developed after #""^1"H"# spectroscopy because the technology was not yet available.
99.99 % of the H atoms in a compound are #""^1"H"#. Even so, the NMR signals are so weak that we need sensitive radio receivers to pick them up.
Another problem with the weak signals is that they tend to get lost in the noise.
Only about 1.1 % of the carbon atoms in a sample are #""^13"C"#. And the magnetic signal from a #""^13"C"# nucleus is only ¼ that of a proton. That makes it about 10 000 times more difficult to detect #""^13"C"# signals.
#""^13"C"# spectroscopy had to await the development of Fourier transform NMR spectroscopy, which could separate the signals from the noise.
Even then, it was difficult to digitize the signal. And the calculations needed huge, expensive computers.
#""^13"C"# NMR spectroscopy did not become widespread until "small" computers were commercially available.
And this started the flowering of NMR in organic chemistry.
