Influence of injector bypass on lifetime of small-particle liquid chromatographic columns

Summary In the case of liquid chromatography columns packed with small (3–5 m) particles and utilized at relatively high flow rates, pressure pulses associated with the sample injection process (caused by a short-duration interruption in mobile phase flow to the column during injection) may result in a reduction of column lifetime. This detrimental effect can be eliminated by the utilization of specially constructed sample injection valves incorporating properly desinged bypass loops. The paper investigates in detail the effect of pressure pulses, describes the criteria and performance of the bypass systems, and documents column life time and performance.Dedicated to Dr. L. S. Ettre on the occasion of his sixtieth birghday.