CONVERTING GRADIENT RETENTION TIMES TO ISOCRATIC RETENTION TIMES IN REVERSED PHASE LIQUID CHROMATOGRAPHY

• Published in: Journal of liquid chromatography & related technologies Vol. 23; no. 10; pp. 1477 - 1487
• Main Author: Kavanagh, P. E.
• Format: Journal Article
• Language: English
• Published: Colchester Taylor & Francis Group 15.05.2000; Taylor & Francis
• Subjects: Analytical chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Exact sciences and technology; Other chromatographic methods; Reversed phase chromatography; Elution; Gradient; Ultraviolet detector; Phase composition; Property composition relationship; Chromatographic retention; HPLC chromatography; Mobile phase; Retention time; Isocratic condition; Conversion
• ISSN: 1082-6076; 1520-572X
• DOI: 10.1081/JLC-100100428

Various methods of converting gradient retention times in reversed phase liquid chromatography to isocratic retention times are compared. The two main methods investigated were the analytical solution to dV m = dV'/k, and the numerical solution to dV m = dV/(1+k). Other methods investigated involved using a quadratic expression for the dependence of log retention factor on mobile phase composition instead of the usual linear function and also inclusion of a correction for extra gradient delay due to void volume of the column. No method gave a good agreement between isocratic retention times estimated from gradient data and experimental isocratic retention times. The method which gave the best agreement was the numerical integration of dV m = dV/(1+k) using the usual linear relationship between log of retention factor and mobile phase composition. A modern spreadsheet was used for all calculations.