Increasing Retention times: Causes and Solutions

 

 

                          Possible Cause                                                                                           Solution
 
 
Decreasing flow rate Check and reset pump flow rate; check for pump cavitation; check for leaking pump seals and other leaks in system. 
Changing mobile-phase composition Cover solvent reservoirs; ensure that gradient system is delivering correct composition. 
Loss of bonded stationary phase  Use mobile-phase pH between pH 2 and pH 8