title: Sub-2 microm porous and nonporous particles for fast separation in reversed-phase high performance liquid chromatography.
abstract: One approach to achieve fast and efficient separations in packed column liquid chromatography (LC) is to reduce eddy diffusion and mass transfer resistance in the mobile phase using short columns packed with small particles. In this study, efficiencies of columns packed with 1.5 and 3.0 microm nonporous and porous particles were compared in reversed-phase LC using nitromethane and a protein as analytes. Nonporous particles provided overall higher efficiency at high linear velocities when nitromethane was used as solute; however, the efficiency difference diminished significantly when the particle size was reduced from 3 to 1.5 microm. Efficiencies for 1.5 microm nonporous particles were considerably higher than those for 1.5 microm porous particles at high linear velocities when a protein, alpha-chymotrypsinogen A (MW 25,000), was used as solute. In addition, the average retention factor for amylbenzene in a column packed with ACQUITY C(18) porous particles was approximately 16 fold higher than for Micra C(18) nonporous particles for aqueous mobile phase compositions containing from 40 to 75% acetonitrile. Pressure drop, sample loading capacity, and separation power were also evaluated and compared for porous and nonporous particles under practical conditions.
authors.affiliation: Department of Analytical Science & Quality Testing, Merck & Co. Inc., RY818-B215, P.O. Box 2000, Rahway, NJ 07065, USA.
authors.forename: Naijun
authors.initials: N
authors.lastname: Wu
authors.forename: Yansheng
authors.initials: Y
authors.lastname: Liu
authors.forename: Milton L
authors.initials: ML
authors.lastname: Lee
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D002919:Chymotrypsinogen / Q000032:analysis / Q000737:chemistry; D008697:Methane / Q000031:analogs & derivatives / Q000737:chemistry; D009595:Nitroparaffins / Q000737:chemistry; D010316:Particle Size; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D009595:Nitroparaffins; D012822:Silicon Dioxide; D002919:Chymotrypsinogen; D008697:Methane; C008640:nitromethane