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ZDD - [W] Generalized Error, Linear Gradient (HPLC Gradient Peaks Only)

This is the Zero Distortion Density (ZDD) used in the GenHVL[W] models.

The [W] model is offered as a ZDD option for HPLC gradient peaks. In most cases, the Gen2HVL or GenHVL[Y], which use a logarithmic gradient, will be the models of choice for fitting HPLC gradient peaks. If the gradient is particularly strong, however, and a peak is dramatically impacted across the span of its specific elution by a linear gradient, and if there is very little intrinsic fronting or tailing arising from the chromatographic distortion, the peak decay may be better described by a linear rather than a logarithmic asymmetry. This model should be deemed experimental, and should always be evaluated alongside either the Gen2HVL or GenHVL[Y] model.

You will not want to use the GenHVL[W] for analytic non-gradient peaks. The linear gradient in the [W] density will actually work against the strongly fronted and tailed shapes arising from high intrinsic chromatographic distortions.

This generalized error's a1 center parameter is the mean of the underlying Normal. The a2 width parameter is the Gaussian width used in the model. The a3 is the power of the decay, 2.0 for Gaussian, >2 for the compaction arising from the gradient. The a4 parameter in the ZDD nomenclature specifies the linear gradient asymmetry, negative for fronting, positive for tailing.

There is no GenNLC[W] model since this [W] ZDD cannot replicate a Giddings decay.



ZDD - [W]3.PNG

a0 = Area

a1 = Center (as mean of underlying Gaussian)

a2 = Width (as SD of underlying Gaussian)

a3= Power of decay (2.0=Gaussian)

a4= Asymmetry (fronted -1 > a4 > 1 tailed)



Built-In Peak Model

  GenErrorLin (Statistical family)

User-Defined Peaks and View Functions

 GenErrorLin(x,area,median,width,shape,power) LinAsym Generalized2 Normal Area

 GenErrorLin_C(x,area,median,width,shape,power) LinAsym Generalized2 Normal Cumulative

 GenErrorLin_CR(x,area,median,width,shape,power) LinAsym Generalized2 Normal Rev. Cumulative

This Generalized Error with Linear Gradient model is part of the unique content in the product covered by its copyright.

C:\1pf2022\Help\home.gif ZDD - [S] ZDD - Giddings