How sensitive and accurate are routine NMR and MS measurements?

The necessary prerequisites to carry out efficient NMR/MS studies and the important points required to avoid inconsistent measurements are discussed. A comparative assessment of the sensitivity and accuracy of NMR, EI-MS and ESI-MS measurements was carried out to evaluate typical laboratory research performance. Accurate NMR measurements are possible in the 10^–1–10^–3 M concentration range, with spectral studies still being possible at concentrations of approximately 10^–4–10^–5 M. EI-MS is more sensitive and can operate at concentrations of 10^–6 M, while commonly available ESI-MS can be efficient up to a concentration of 10^–18 M.