Interested in Language
I find a sentence below in a jounal article (website:ScienceDirect.com - Peptides - A new family of cystine knot peptides from the seeds of Momordica cochinchinensis), saying "at a flow rate of either 0.3 or 1 mL/min". I am confusing. LC–MS was carried out on an HP 1100 Series HPLC (Agilent Technologies) that was connected to an ESI-TOF mass spectrometer (Applied Biosystems) at a flow rate of either 0.3 or 1 mL/min (solvent A: Milli-Q water with 0.1% formic acid; solvent B: 90% acetonitrile in Milli-Q water with 0.1% formic acid).
Should it be "at flow rate of either 0.3 or 1 mL/min? why?
There is only one flow rate, but two possibilities. The text is right. You can't have two simultaneous flow rates in a single thing- you have to choose one at a time.