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RRT Formula:
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Relative Retention Time (RRT) is a dimensionless parameter used in chromatography to compare the retention time of a sample compound to that of a reference standard. It provides a normalized measure that is less affected by variations in chromatographic conditions.
The calculator uses the RRT formula:
Where:
Explanation: RRT normalizes retention times, making comparisons between different chromatographic runs more reliable and reducing the impact of system variations.
Details: RRT is crucial in HPLC method development, peak identification, and quality control. It helps in confirming compound identity and monitoring chromatographic system performance.
Tips: Enter both retention times in minutes. Ensure values are positive and the standard retention time is not zero. The result is a unitless ratio.
Q1: Why use RRT instead of absolute retention time?
A: RRT is more reproducible across different chromatographic systems and conditions, as it accounts for variations in flow rate, column length, and temperature.
Q2: What are typical RRT values?
A: RRT values typically range from 0 to 2, with 1 indicating the compound elutes at the same time as the standard. Values less than 1 indicate earlier elution.
Q3: How to choose a reference standard?
A: Choose a stable, well-characterized compound that elutes in the middle of the chromatographic run and doesn't interfere with sample components.
Q4: What affects RRT values?
A: Mobile phase composition, column type, temperature, and pH can affect RRT. Method transfer between systems may require RRT verification.
Q5: Is RRT used in regulatory submissions?
A: Yes, RRT is commonly used in pharmaceutical analysis and regulatory submissions for method specificity and peak identification.