How sensitive and accurate are routine NMR and MS measurements?

Abstract

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.