HALO®-5 HPLC columns  

The HALO®-5 Column is based on the same Fused-Core particle technology as the HALO® column with 2.7 µm particle. Compared to standard HPLC columns with totally porous 5 µm particles, the HALO®-5 columns feature:

high efficiency and fast flow rates like a UHPLC column with particles < 3µm

durability and ease of use of an HPLC column with 5 µm particles

low back pressure allowing the use of legacy HPLC instruments

Originally, HALO® column were designed and manufactured as UHPLC column. Now the proven Fused-Core particle technology, which has made HALO® UHPLC columns a success, has been used to create a new generation of standard HPLC columns with extraordinary performance, the HALO®-5 HPLC columns.

The use of UHPLC is growing rapidly, but the high costs and complexity of UHPLC are still factors not to be underestimated. This and the large installed base of traditional HPLC equipment mean that HPLC separations will continue to be the dominant method for liquid chromatography for years to come. To meet the need for improved speed and resolution capacities, the HALO®-5 column based on the Fused-Core particle technology was developed.

Fused-Core particles are manufactured by fusing a porous silica layer onto a solid silica particle. The extremely small particle size distribution and the short diffusion path of these porous HALO® particles reduce both eddy diffusion and axial dispersion and thereby minimise peak broadening.

   
HALO®-5: faster separation, higher resolution  
   
HALO®-5: highest plates per column back pressure  
It is well known that columns packed with larger particles deliver more theoretical plates per unit of column back pressure than columns packed with smaller particles. The plates per pressure ratio of the HALO®-5 column is significantly higher than what is seen with other columns packed with totally porous 5 µm particles. This makes the HALO®-5 column a powerful tool for the separation of complex mixtures that need a large number of theoretical plates and when HPLC equipment with limited pressure capability is used.
   
Kinetic Plot comparison  
One of the distinguishing characteristics of Fused-Core particles is the unusually narrow size distribution (dp90/dp10 ~ 1.5) compared to totally porous particles (dp90/dp10 < 1.15). This plus the high density of the Fused-Core particle facilitate the packing of the column with remarkably good reduced plate heights „h“. It has generally been assumed that a plate height “h” of 2 was the practical limit that could be achieved with columns and few commercial columns even achieve “h” values less than 2.5. HALO®-5 columns typically have “h” values less than 1.3 particle diameters. This explains why HALO®-5 columns by far exceed standard HPLC columns packed with totally porous 5 µm particles in efficiency and separation power and why they provide comparable efficiencies to HPLC columns packed with 3 µm totally porous particles but at half the pressure.
   

HALO®-5 specifications
• Solid core particle with a 0.6 μm porous layer fused to the surface
• Ultra-pure “Type B” Silica
• pH range 2 - 9, max. temp. 60 °C, max. pressure 9000 psi/600 bar,
• pore size 90 Å
• 90 m2/g surface area (equivalent to 150 - 200 m2/g totally porous particles)

   

Excellent performance for a broad range of analyte polarities. Separations are primarily due to hydrophobic interactions and differences in hydrophobicity among analytes.

C18- will strongly retain polar and moderately polar analytes
C8 - provides similar selectivity to C18 but with less retention

Separations occur both due to hydrophobic and π-π interactions. Enhanced retention and selectivity for aromatic and unsaturated analytes especially those with electron withdrawing groups and halogens. Compatible with aqueous mobile phases.

Separations take place due to multiple types and degrees of analyte interactions including hydrophobic, π-π, dipole-dipole and hydrogen bonding. Can be used in the HILIC mode with mobile phases containing greater than 80% acetonitrile. Enhanced selectivity for stereoisomers. Compatible with highly aqueous mobile phases.

Provides strong dipole-dipole interactions with analytes and weak hydrophobic interactions. Suitable for use in reversed-phase, HILIC, and normal-phase modes. Rapid equilibration with low bleed for high throughput LC-MS applications. Extra stable bonding with sterically protected ligand provides improved stability and performance compared to conventional CN phases, especially at low pH (1–4).

The Penta-HILIC is specifically designed and intended for hydrophilic interaction liquid chromatography, HILIC. The HALO® Penta-HILIC stationary phase is a highly polar ligand that possesses 5 hydroxyl groups tethered to the silica via novel proprietary linkage chemistry. The retention mechanism offered by the Penta-HILIC phase is a combination of hydrophilic interaction and weak hydrophobic binding interaction. Retention in HILIC mode as a function of mobile phase is opposite that of reversed phase. For example, increasing the mobile phase strength involves increasing the polarity of the mobile phase by increasing the aqueous component. Penta-HILIC is particularly recommended for the separation of highly polar analytes that are poorly retained in reversed phase mode. The Penta-HILIC phase is also recommended for LC-MS applications because of the MS friendly mobile phase conditions typically used with Penta-HILIC.

The HILIC phase is an unbonded pure silica. It can be used for either normal-phase or HILIC mode of separation. When used in HILIC mode, it is recommended for similar applications as the Penta-HILIC phase described previously. Separations on HILIC are expected to be similar to Penta-HILIC, although subtle differences in selectivity will often occur, favouring one phase over the other when developing an optimized HILIC separation.

HALO® semi preparative columns
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HPLC Columns & Accessories Index
HALO® Columns 2.7 µm - 90Å & 160Å
HALO®-5 Columns 5 µm - 90Å
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