In contrast, in the vaping experiments, the 1 H NMR spectrum of the impinger solution showed the presence of N-benzylacetamide within minutes of aerosol generation and collection. Moreover, had CBN-OAc-D 3 (rather than ketene-D 2 ) directly reacted with benzylamine, a septet arising from -CD 3 splitting (from N-benzylacetamide-D 3 ) would have been observed in the C NMR, rather than the quintet shown in Figure .