I agree - I've often heard (and said) things like "Make up a solution of 0.05 M citric acid in the same buffer you've been using, at pH 9." Also: if it's just

I agree - I've often heard (and said) things like "Make up a solution of 0.05 M citric acid in the same buffer you've been using, at pH 9." Also: if it's just a proposed intermediate composition (as is mentioned in other comments as the author's explanation), the comment could very well mean to think up something plausible to propose, with the understanding that most readers will think to themselves that although it wasn't actually measured, there is a plausible route. It looks to me like this particular bit of the paper really isn't the main thrust, and so doesn't need to be proven as rigorously. So in my mind it's not a huge smoking gun. I've personally seen a couple papers submitted for review where figures were crudely photoshopped. The usual play here is to be gentlemanly and to assume that they were just throwing in a dummy figure to be replaced later when they got presentable data... except they forgot to make the change. This is a minor embarrassment for the authors (who can now expect closer scrutiny!), but also for the journal... they should be keeping a close eye on what they're publishing!