The integrator identifies the start of the peak with a baseline point determined by the peak recognition algorithm. The peak recognition algorithm first compares the outputs of the peak recognition filters with the value of the initial slope sensitivity, to increase or decrease the up-slope accumulator. The integrator declares the point at which the value of the up-slope accumulator is ≥15 the point that indicates that a peak has begun.
In Incremental Values to Upslope Accumulator the expected peak width determines which filter’s slope and curvature values are compared with the Slope Sensitivity. For example, when the expected peak width is small, Filter 1 numbers are added to the up-slope accumulator. If the expected peak width increases, then the numbers for Filter 2 and, eventually, Filter 3 are used.
When the value of the up-slope accumulator is ≥15, the algorithm recognizes that a peak may be starting.
Derivative Filter 1 - 3 Outputs against Slope Sensitivity | Filter 1 | Filter 2 | Filter 3 |
|---|---|---|---|
Slope > Slope Sensitivity | +8 | +5 |
+3 |
Curvature > Slope Sensitivity |
+0 | +2 |
+1 |
Slope < (-) Slope Sensitivity |
-8 | -5 |
-3 |
Slope < |Slope Sensitivity| |
-4 | -2 |
-1 |
Curvature < (-) Slope Sensitivity |
-0 | -2 |
-1 |
In Incremental Values for Downslope Accumulator the expected peak width determines which filter’s slope and curvature values are compared with the Slope Sensitivity. For example, when the expected peak width is small, Filter 1 numbers are added to the down-slope accumulator. If the expected peak width increases, then the numbers for Filter 2 and, eventually, Filter 3 are used.
When the value of the down-slope accumulator is ≥15, the algorithm recognizes that a peak may be ending.
Derivative Filter 1 - 3 Outputs against Slope Sensitivity | Filter 1 | Filter 2 | Filter 3 |
|---|---|---|---|
Slope < (-) Slope Sensitivity | +8 | +5 |
+3 |
Curvature < (-) Slope Sensitivity |
+0 | +2 |
+1 |
Slope > Slope Sensitivity |
-11 | -7 | -4 |
|
Slope > |Slope Sensitivity| |
-28 | -18 | -11 |
|
Curvature > Slope Sensitivity |
-0 | -2 |
-1 |
The peak apex is recognized as the highest point in the chromatogram by constructing a parabolic fit that passes through the highest data points.