Are elemental analysis guidelines appropriate?

As graduate students working side by side in a glovebox, two of us (Caleb Martin and Jason Dutton) experienced pressure to obtain elemental analysis data meeting strict journal standards. While we could acquire and analyse other spectral data (such as NMR, infrared, and mass spectra) for new compounds on-site, elemental analysis was performed by a third party. If the results sent to us deviated from expected values, we could do little more than shrug our shoulders, point to our clean NMR spectra, and try to synthesise or purify a ‘better’ sample, which either gave suitable numbers, or not, after a delay of several weeks.

Moreover, the values returned had no error bars or corroborating raw data. There is also no direction on how to treat the data on a resubmitted sample nor, if the company ran duplicate analyses, on how the multiple numbers should be interpreted. Anecdotal comments from the synthetic community indicate it is common practice in many groups to resend a sample from the same batch and simply select the best result. Journals generally required values within ±0.4% of the calculated values for carbon, hydrogen and nitrogen in a proposed formula but provided no rationalisation for this threshold. Years later, in our academic positions, we faced this situation from a different angle. Elemental analysis was an expense to our limited budgets, and unsatisfactory results delayed publication.