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Chromatographic peak resolution is given by = + where t R is the retention time and w b is the peak width at baseline. The bigger the time-difference and/or the smaller the bandwidths, the better the resolution of the compounds.
The van Deemter equation is a hyperbolic function that predicts that there is an optimum velocity at which there will be the minimum variance per unit column length and, thence, a maximum efficiency. The van Deemter equation was the result of the first application of rate theory to the chromatography elution process.
The Purnell equation is an equation used in analytical chemistry to calculate the resolution R s between two peaks in a chromatogram. [1] [2]= (′ + ′) where R s is the resolution between the two peaks
A high value for resolution corresponding to good separation of peaks is similar to the convention used with chromatography separations, [13] although it is important to note that the definitions are not the same. [14] High resolution indicating better peak separation is also used in ion mobility spectrometry. [15]
PeakFit is an automated nonlinear peak separation and analysis software package for scientists performing spectroscopy, chromatography and electrophoresis.. PeakFit automatically finds and fits up to 100 peaks to a data set, at a time, enabling users to characterize peaks and find the best equation that fits their data.
The retention time is the time from the start of signal detection to the time of the peak height of the Gaussian curve. From the variables in the figure above, the resolution, plate number, and plate height of the column plate model can be calculated using the equations: Resolution (R s): R s = 2(t RB – t RA)/(w B + w A), where:
The Scherrer equation, in X-ray diffraction and crystallography, is a formula that relates the size of sub-micrometre crystallites in a solid to the broadening of a peak in a diffraction pattern. It is often referred to, incorrectly, as a formula for particle size measurement or analysis.
, the carbon number of n-alkane peak heading peak i, the retention time of compound i, minutes, the air peak, void time in average velocity = /, minutes; The Kovats index also applies to packed columns with an equivalent equation: