Standard Deviation Formula:
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Definition: This calculation determines the standard deviation of peak broadening in chromatography based on column length and plate count.
Purpose: It helps chromatographers evaluate column efficiency and peak broadening characteristics.
The calculator uses the formula:
Where:
Explanation: The standard deviation decreases as the square root of the number of theoretical plates increases, indicating better column efficiency.
Details: A smaller standard deviation indicates sharper peaks and better separation efficiency in chromatographic systems.
Tips: Enter the column length in meters and the number of theoretical plates (must be ≥ 1). Both values must be positive numbers.
Q1: What does standard deviation represent in chromatography?
A: It quantifies peak broadening - smaller values indicate narrower, more efficient peaks.
Q2: How is number of theoretical plates determined?
A: Typically calculated from retention time and peak width at half height.
Q3: Why does standard deviation decrease with more plates?
A: More plates mean more equilibrium steps, leading to less band broadening.
Q4: What's a typical range for theoretical plates?
A: Good columns typically have 10,000-20,000 plates per meter.
Q5: How does column length affect standard deviation?
A: Longer columns increase standard deviation proportionally, all else being equal.