Mechanical Strength of YMC Silica
High Performance Silica Supports
Spherical media for long column life: YMC spherical media provide high performance with long column lifetimes. Spherical particles with a narrow particle size distribution pack more uniformly than “spheroidal” or irregular supports and produce only a low pressure drop. The greater mechanical stability of the column bed eliminates premature voiding. With the use of DAC-systems the material may be packed and repacked several times.
In a test procedure applying repeated packing and unpacking steps YMC*Gel shows high mechanical strength.
Fig. 1: Change of back pressure after repeated packing.
Fig. 2: Bed pressure drop increase after repeated packing.
Test-conditions:
YMC*Gel ODS-A, pore size: 12 nm, particle size: 10 µm (spherical particles)
Column: Dynamic Axial Compression column (50 mm i.d.)
Bed length: 50 mm
Flow rate: 150ml/min.
Mobile phase: Methanol / Water 85 / 15
Packing pressure: 6.4 MPa (= 64 bar)
Chemical Stability of YMC Silica
State-of-the-Art Bonding and Endcapping
Silica supports are the foundation of most advanced HPLC media, enabling these phases to tolerate the high pressures of modern HPLC. When a silica particle is bonded, “residual silanols” (unbonded surface silanol sites: -SiOH) can interact with polar samples and eluents. These interactions are desirable with some samples. With basic samples and aqueous eluents, however, residual silanols can cause problems with peak symmetry and shorten column life. “Endcapping” is a process by which residual silanols are bonded to minimise interaction with solute molecules. The nature and completeness of the endcapping process greatly influence the performance and quality of an HPLC column and, ultimately, the separation.
YMC has devoted years of bonding and endcapping research to its line of stationary phases. YMC combines this know-how with high-surface silica supports to produce phases with a combination of selectivity, efficiency and durability available only from YMC.
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