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522 M. Daszykowski eł al.

To illustrate this, Fig. la shows the original chromatogram of sample 12 (extract of S. tńloba), divided into twenty time intervals of 4 min each. In each time section, the number of the sampling points was determined and is visualized in Fig. Ib.

From this figurę, it can easily be understood that each section consists of a different number of sampling points. In terms of the number of points, the width of individual sections can be relatively large, and rangę from 110 to 2048 sampling points. As shown in Fig. Ic, linear interpolation enables adjustment of the acquisition ratę and, finally, each section has the same number of sampling points.

40    50

time [min]

ttme (mm)

Fig. 1. (a) Original HPLC chromatogram of sample 12 (extract of S. triloba) divided into twenty time sections of 4 min each; (b) number of sampling points in each time window; (c) number of points in each time window after linear interpolation of a signal

to a length of 3000 sampling points

Moreover, linear interpolation preserves the peak shapes. It seems the best option to adjust the number of points on the new time axis in accor-dance with the shortest chromatogram. Linear interpolation can also be used to reduce the length of a chromatogram. Very often, the number of the data points in a chromatogram can be much reduced, virtually without any