Flow Injection Tutorial

The advantage of the SFC reaction rate measurement is that variation of the baseline (as shown in red box B) do not affect the reproducibility of an assay, since the readout is based on the slope of the reaction rate curve (B,C). This readout is obtained by means of software protocol (A) by setting the time of baseline subtraction point (BS green box) and window (WIN yellow box) in such a way that these times bracket the linear portion of reaction rate curves (B,C, green and yellow bars). This, reaction rate measurement is a valuable feature for assay of real life samples, when the background color or samples or reagent contribute to absorbance readings of SFC end point measurement. Reaction rate method yields good reproducibility even when the calibration range is extended down to low absorbancies, such as at 5 ppM (E) and at 1 ppM (F) of glucose. Note that this approach is applicable to a wide variety of enzymatic assays.