Physical and Chemical Characteristics of Zymor Stationary Phases 

In order to produce the variety of stationary phases offered by Zymor, different chemical functionalities are covalently bonded onto totally porous silica particles. Particles are available in various sizes and shapes, and with a range of pore sizes. The various bonded groups are described below. After a primary bonding, some phases are endcapped to further reduce the number of residual silanols.

 Particle Size

Particle size is the diameter of the stationary phase particle in microns (μ). The particle sizes quoted, are the mean size for that material. Zymor carefully monitors the particle size distribution of its stationary to maintain batch to batch reproducibility.

Zymor offers particle sizes of 10, 5 and 3 microns. Smaller particles offer more efficiency but produce higher backpressure. Extra care must be given to filtration of samples and mobile phases when using 5μ and 3μ particles compared to 10μ particles.

Pore Size

Pore size is the average size of the pores in the particle stationary phase in angstroms, (Å). The amount of surface area in meters squared, which is available for bonding, and therefore available for analyte retention, is dependent on pore size. A larger pore size means bigger holes in the particle, leaving less surface area than would many smaller holes. Zymor offers stationary phases with pore sizes of 60, 100, 125, 200 and 300A.

 Column Dimensions

Column dimensions are described by the column length, either in mm, and the column inner diameter in mm ID. The size of the column is determined by its intended use by the particle size of the stationary phase. For example, 3 micron particles are packed in shorter column lengths because a 250mm column would, under usual circumstances, generate too much backpressure for a typical HPLC system. Also, because the 3 micron particles are very efficient, a shorter column probably has enough theoretical plates for the required separation.

 The typical analytical column inner diameter has been 4.6mm. In order to reduce the volume of the column effluent, operators of LC-MS systems have looked toward smaller ID columns.

 Zymor offers analytical columns in column ID's of 4.6, 4.0, 3.0, and 2.0mm. Semi-Prep columns are available in ID's of 10.0, 21.2, 30.0, and 50mm.