Width of Peak Formula:
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Definition: This calculator determines the width of a chromatographic peak at its base using the retention time and number of theoretical plates.
Purpose: It helps in chromatographic analysis to evaluate peak shape and column efficiency.
The calculator uses the formula:
Where:
Explanation: The width of the peak is directly proportional to the retention time and inversely proportional to the square root of the number of theoretical plates.
Details: Peak width is crucial for determining resolution between adjacent peaks and assessing column efficiency in chromatographic separations.
Tips: Enter the retention time in seconds and the number of theoretical plates. Both values must be positive numbers.
Q1: What is the significance of the number 4 in the formula?
A: The factor of 4 accounts for the fact that peak width is typically measured at the baseline, which is approximately 4 standard deviations of the Gaussian peak.
Q2: How is the number of theoretical plates determined?
A: The number of theoretical plates (N) is calculated from the retention time and peak width using: \( N = 16(t_r/w)^2 \).
Q3: What does a narrower peak indicate?
A: Narrower peaks (smaller width) generally indicate better column efficiency and higher resolution between adjacent peaks.
Q4: Can this formula be used for non-Gaussian peaks?
A: The formula works best for symmetrical (Gaussian) peaks. For tailing or fronting peaks, alternative methods may be needed.
Q5: How does retention time affect peak width?
A: For a given number of theoretical plates, peaks with longer retention times will be wider due to longitudinal diffusion.