A flow injection analysis (FIA) experiment relies on analyte flowing through a series of tubes before reaching the detector.

An analyte is a substance whose chemical constituents are being identified and measured.

The tubes are useful for introducing reagents to cause colour changes, mixing, or chemical changes necessary for analysis, providing a useful way to automate an experiment. However, as a result of flowing through a series of tubes the analyte is not always distributed evenly. Instead, the traces have a sharply rising edge that slowly trails off. Fig 24.7 shows some idealised data from an FIA experiment. The following table contains some typical data.

Plot the data, and use numerical integration to estimate the area of the trace between t = 0.3 min and t = 1 min and thus quantify the amount of analyte flowing past the detector. The units of the signal are not specified, but the amount of analyte is given by the area under the signal curve.