Organic chemists have been taking NMR spectra for quite a while now. Routine use came on in the 1960s, and higher-field instruments went from exotic big-ticket items in the 1970s to ordinary equipment in the 1980s. But NMR can tell you more about your sample than you wanted to know (good analytical techniques are annoying that way). So what to do when you have those little peaks showing up where no peaks should be?
The correct answer is “Live with ’em or clean up your sample”, but wouldn’t it be so much easier and faster to just clean up the spectrum? After all, that’s all that most people are ever going to see – right? This little line of thought has occurred to countless chemists over the years. Back In The Day, the technology needed to remove solvent peaks, evidence of isomers, and other pesky impurities was little more than a bottle of white-out and a pen (to redraw the lovely flat baseline once the extra peaks were daubed away). Making a photocopy of the altered spectrum gave you publication-ready purity in one easy step.
NMR spectra are probably the most-doctored of the bunch, but LC/MS and HPLC traces are very capable of showing you peaks you didn’t want to see, either. These days there are all sorts of digital means to accomplish this deception, although I’ve no doubt that the white-out bottle is still deployed. In case anyone had any doubt about that, last month Amos Smith, well-known synthetic organic chemist and editor of Organic Letters, had this to say in a special editorial comment in the journal:
Recently, with the addition of a Data Analyst to our staff, Organic Letters has begun checking the submitted Supporting Information more closely. As a result of this increased scrutiny, we have discovered several instances where reported spectra had been edited to remove evidence of impurities.
Such acts of data manipulation are unacceptable. Even if the experimental yields and conclusions of a study are not affected, ANY manipulation of research data casts doubts on the overall integrity and validity of the work reported.
That it does. He went on to serve notice on authors that the journal will be checking, and will be enforcing and penalizing. And you can tell that Smith and the Org Lett staff have followed up on some of these already, because they’ve already had a chance to hear the default excuse:
In some of the cases that we have investigated further, the Corresponding Author asserted that a student had edited the spectra without the Corresponding Author’s knowledge. This is not an acceptable excuse! The Corresponding Author (who is typically also the research supervisor of the work performed) is ultimately responsible for warranting the integrity of the content of the submitted manuscript. . .
As the editorial goes on the say, and quite rightly, if a student did indeed alter the spectrum before showing it to the boss, it’s very likely because the boss was running a group whose unspoken rule was that only perfection was acceptable. And that’s an invitation to fraud, large and small. I’m glad to see statements like Smith’s – the only ways to keep down this sort of data manipulation are to make the rewards for it small, increase the chances of it being found out, and make the consequences for it real.
As for those, the editorial speaks only of “significant penalties”. But I have some ideas for those that might help people think twice about the data clean-up process. How about a special correction in the journal, showing the altered spectra, with red circles around the parts that had been flattened out? And a copy of the same to the relevant granting agencies and department heads? That might help get the message out, you think?
As an aside, I wanted to mention that I have seen someone stand right up and take responsibility for extra peaks in an NMR. Sort of. I saw a person once presenting what was supposed to be the final product’s spectrum, only there were several other singlet peaks scattered around. “What are those?” came the inevitable question. “Water” was the answer. “Umm. . .how many water peaks, exactly?” “Oh, this one is water in solution. And this one is water complexed with the compound. And this one is water adsorbed to the inside of the NMR tube. And this one is water adsorbed to the outside of the. . .” It took a little while for order to be restored at that point. . .