title: Absolute measurement of internal volume changes inside the pulse damper: discrepancy between delay and dwell volumes.
abstract: We have developed a novel technique for the absolute determination of the mobile phase volume stored inside of a variable volume pulse damper at different pressures. Using an Agilent HPLC pulse damper we found a linear volume increase of approximately 1 microL/bar. We found that pump pressurization is a relatively slow process and takes approximately 1 min to reach 90% and takes approximately 2 min to reach 99% equilibration at flow rates below 1 mL/min. During pump pressurization, column flow rate will be less than the pre-set, since part of the mobile phase is retained inside of the pulse damper. During our experiments we observed a discrepancy between data obtained by UV techniques and direct absolute measurements. This difference can be explained by a fundamental difference between the gradient delay volume and dead (dwell) volume.
authors.affiliation: Analytical Core Laboratory, Institute for Clinical and Translational Research, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY 10461, USA. eduard.rogatsky@einstein.yu.edu
authors.forename: Eduard
authors.initials: E
authors.lastname: Rogatsky
authors.forename: Zheng
authors.initials: Z
authors.lastname: Zheng
authors.forename: Daniel
authors.initials: D
authors.lastname: Stein
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D011312:Pressure; D014466:Ultraviolet Rays