HELIX CHROMATOGRAPHY

 

In recent years, two technologies, mixed-mode chromatography and core-shell particles, emerged and gained popularity as tools offering new selectivity and speed for analysis of complex mixtures.Core-shell particles are constructed with solid core and porous outer layer. This porous layer is used as a stationary support for chemical attachment of specific separation phases. The reduced pore length offers faster diffusion of molecules and as a result has the ability to do chromatography faster compared to particles with through-pore structure. The same result can be achieved with smaller particles, but then the pressure needs to be higher in order to produce the same flow rate and speed of analysis. 

 

When a single mode of interaction is employed on a reversed-phase column, compounds elute according to their hydrophobicity and analytes with similar hydrophobicity may co-elute or show poor resolution (reversed-phase example). An opposite approach is to use ion-exchange chromatography, where compounds are retained based on their ionic properties. Similarly, using ion-exchange chromatography, other compounds may be closely eluting because they are identical in terms of the strength of ionic interaction between stationary phase and analyte (ion-exchange example).

In mixed-mode chromatography you have two interactions – reversed-phase and ion-exchange and you are exploring a very small difference in reversed-phase and ionic properties of compounds. These differences are enhanced due to synergy of two mechanisms which results in much better separation (mixed-mode example). Core-shell technology offers the unique ability to achieve high efficiency at higher flow rates whilst generating back pressures which can be achieved using traditional HPLC systems. This offers the end user the opportunity to improve separation speed and quality without the requirement to  purchase UHPLC equipment. We have recognized the exciting opportunities afforded by combining these two great technologies in stationary phases which achieve unique selectivity and high efficiency with traditional HPLC systems which are rated to 4000 or 6000 psi. HELIX CHROMATOGRAPHY has developed a new generation of unique stationary phases, combining mixed-mode and core-shell approaches -  Coresep™.
Mixed-mode columns offer much higher capacity and retention than traditional reversed-phase columns. Since the surface area of core-shell particles is reduced, mixed-mode phases address potential loadability issues whilst maintaining the selectivity advantages of multiple interactions. Newly optimized ligand density and ionic / hydrophobic ratios further increases the capacity of mixed-mode core-shell columns.