1. What is Capacity Factor?

Definition: The capacity factor (k_c') is a parameter that describes how long a compound is retained on the chromatography column relative to the mobile phase flow.

Purpose: It helps in characterizing the retention behavior of compounds in chromatographic separations.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( k_c' \) — Capacity factor (dimensionless)
• \( K \) — Partition coefficient (dimensionless)
• \( V_s \) — Volume of stationary phase (m³)
• \( V_{mobile} \) — Volume of mobile phase (m³)

Explanation: The capacity factor is directly proportional to the partition coefficient and the ratio of stationary to mobile phase volumes.

3. Importance of Capacity Factor

Details: The capacity factor is crucial for:

• Determining retention times in chromatography
• Optimizing separation conditions
• Comparing column performance
• Developing analytical methods

4. Using the Calculator

Tips:

• Enter the partition coefficient (K) - typically ranges from 0.1 to 100
• Enter volumes in cubic meters (m³)
• Typical column volumes range from 1e-6 to 1e-3 m³
• All values must be positive numbers

5. Frequently Asked Questions (FAQ)

Q1: What is a good capacity factor value?
A: Ideal values are typically between 1 and 10. Values below 1 indicate poor retention, while values above 10 may result in excessively long retention times.

Q2: How does capacity factor relate to retention time?
A: Retention time (t_R) = t₀(1 + k_c'), where t₀ is the void time.

Q3: What affects the partition coefficient (K)?
A: K depends on the compound's chemical nature, stationary phase chemistry, mobile phase composition, and temperature.

Q4: Can capacity factor be less than 1?
A: Yes, but values < 1 indicate the compound spends more time in the mobile phase than stationary phase.

Q5: How do I measure the phase volumes?
A: Stationary phase volume is determined by column dimensions and packing density. Mobile phase volume can be measured by void time experiments.