“…The equations accurately describe the exponential 'rise' and 'fall' curves that define a FI peak. Jordan and Pardue 29 have recently shown that experimental concentration-time profi les are exactly those predicted by theory. Other work in the area of time-based FI methods has shown that time intervals predicted by the equations are accurate, even under non WST conditions, 30 but the validity of the equations to accurately defi ne the FI peak profi le is limited under such experimental con ditions.…”