HPLC Materials
Polymeric HPLC materials
Redstone develops polymeric chromatography materials for high pressure analytical applications, and for semi-preparative and preparative work with larger particles.
The current development portfolio holds these highly cross-linked polymeric resins:
- DVB/Styrene reversed phase resins
- Hydrophilic polymeric resins
- Ion exchange resins, both strong and weak cation and anion exchangers
- Particle sizes: 10 um, 50 um, 70 to 200 um and industrial 200 to 1200 um
- Pore sizes: 100 A, 300 A, 500 A, 1000 A and above 1000 A on request
Microscopic picture of polymeric reversed phase particles, average size 10 um.
Scanning electron microscope image of a 10 um porous DVB/Styrene resin at 25 000x magnification.
First prototype separations
Below are example separations of the model compounds Gly-Leu-Tyr and aspartame, and of insulin against ACTH, on prototype reversed phase resins based on DVB/Styrene with 100 A or 300 A pores.
Separation of peptides
GLT (Gly-Leu-Tyr, first peak) and aspartame (Asp-Phe-OMe, second peak). Mobile phase: water with 0.1 % formic acid, 10 to 100 % AcN over 60 min. Flow 0.5 ml/min. Reversed phase resin, DVB/Styrene with 100 A pores.
Adrenocorticotropic hormone (ACTH, first peak) and insulin (second peak). Mobile phase: water with 0.1 % formic acid, 10 to 50 % AcN over 60 min. Flow 0.2 ml/min. Reversed phase resin, DVB/Styrene with 300 A pores.
Separation of alkaloids and amines
Example of separation of alkaloids on a novel silica-coated weak cation exchanger.
Prototype material
| Material type | Coated silica |
| Particle size | 10 um |
| Pore size | 100 A |
| Surface area | 450 m2/g |
| Functionality | -COOH |
| Capacity | 1 mmol/g |
Separation of organic alkaloids. Column: prototype Temiz WCX. Flow 1.5 ml/min. Eluent: water, AcN and formic acid gradient. Detection at 240 nm. Injection: caffeine, melamine and quinine mixture.
Master thesis with Lund University
Several of our reversed phase prototypes were evaluated in a master thesis carried out together with Lund University, Sweden.
Popular Abstract
Introduction: Separation of bio-based compounds with therapeutic activities can be achieved on polymeric media and not only on traditional silica particles. It’s essential to identify upsides and downsides between the two material classes, such as pH range of use and mechanical tolerance, to understand which one is more suited to the specific separation mode.
Background: Current acceptable purity of some biological formulations is minimum 90% and the relative impurities can lead to side-effects, even strongly negative ones. Current traditional silica-based separation media undergo degradation at high pH, when cleaning of the stationary phase is carried out with hydroxide solutions to denature and wash away biological compounds. The most recent silica type (C) is able to withstand up to pH 11, but its cost renders it a difficult solution for scaling up production, and polymeric media may be the most satisfying solution in this regard, constituting a good middle ground between cost and performance.
Aim(s): The aim of this thesis project is to characterize styrene-divinylbenzene copolymers obtained through novel synthesis methods and their chromatographic performance in the development of separation and purification methods. This material was chosen for having a large research background already present, on which the company developed its own methods of synthesis.
Methods: Characterization of resins by light scattering, BJH analysis and optical microscope to determine particle and pore size, then test of the resins in HPLC columns with a few representative peptides to determine chromatographic performance, including column efficiency and resolution.
Results: Laser diffraction and microscope pictures are in agreement with each other and the particle size distributions are centered either at 6 or 11 µm (D50). BJH pore size analysis shows results mostly centered at around 250 Å, however a few samples have pore sizes in the 60 Å range, for both smaller and larger particles. The chromatographic gradient was optimized throughout the whole project for the resin basis, regardless of the column length and particle size, adjusting the flow for each column until a similar starting pressure was achieved. The HETP parameter was evaluated for each column, as well as the resolution of the different peaks.
Conclusion: Thanks to proprietary synthesis methods, a new series of polymeric materials were developed and, after screening, a few representative samples provided comparable results when compared to current commercial alternatives.
Custom HPLC materials
First products are on the way. We also offer custom development of tailor-made resins for HPLC materials, evaluated case by case. Get in touch with suggestions or product enquiries.
TAILORED RESINS