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Trapezoid method
This method consists in calculate the peak in time area drawing rectangles
between two consecutive points and summing the resulting area. This rectangle is drawn using the retention time as the rectangle base and the intensity
as the height. In order to fill the existing gaps between the rectangle and the
peak in time shape a triangle will be drawn, and the resulting area will be
summed as well.
Figure 42: Using rectangles and triangles in order to calculate a bell shape
area.
As can be seen in the previous figure, a rectangle has been formed every two
points from which can be calculated the area.
arearectangle = base ∗ height
= (retT2 − retT1 ) ∗ intensity1
At this point a triangle will be drawn in order to fill the existing gap (shape’s
left side) or subtract it from the previously drawn rectangle (shape’s right
side). In order to do it, the next formula will be used:
base ∗ height
2
(retT2 − retT1 ) ∗ (intensity2 − intensity1 )
=
2
areatriangle =
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