Use this chemistry calculator to reproduce a named relationship with explicit quantities and units for study, laboratory planning, or an independent numerical check.

Retention factor of A

Required number input.

Retention factor of B

Required number input.

Compute chromatographic selectivity alpha as the retention factor of peak B divided by the retention factor of peak A. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Selectivity

The resulting selectivity returned as a number.

• Chromatographic plate, resolution, retention, and peak-shape formulas summarize an observed chromatogram. They do not model detector response, integration choices, extra-column broadening, gradient elution, overload, or uncertainty in locating peak boundaries.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check units and significant figures, compare the result with limiting cases, and use measured or source-specific constants where available. Laboratory, safety, and regulatory decisions require validated methods and appropriate uncertainty analysis.

• Chromatographic Resolution

  Compute chromatographic resolution Rs as twice the retention time separation divided by the summed baseline peak widths.

• Retention Factor k

  Compute the chromatographic retention factor k as adjusted retention time divided by the column dead time.

• Peak Asymmetry Factor

  Compute the peak asymmetry factor as the tail half width divided by the front half width measured at ten percent peak height.