FINEX IN CHROMATOGRAPHIC RESINS
THE POWER OF CHROMATOGRAPHIC RESINS
Finex is developing and manufacturing tailor made chromatographic resins for industrial systems. A correctly designed and selected resin can improve the process capacity, yield or product purity as well as generating significant reductions in operational costs (such as evaporation). Resin particle size and particle size distribution, the degree of cross-linking and the resin ionic form are the most important parameters adjusted. Finex also provides technical support and analysis of resin properties and characteristics for troubleshooting; also most importantly, basic operator training for appropriate resin handling and chromatography know-how.
BASICS OF CHROMATOGRAPHY
Chromatography is a technique that separates dissolved (usually aqueous) components from each other. It finds applications in the enrichment or recovery of certain molecules or in the removal of harmful components. The chromatography separation system consists of the stationary phase (resin) and the moving phase (eluent); the mixture of the components is usually eluted downwards through the stationary phase and different mechanisms and interactions between the stationary phase and the components dissolved in the eluent result in the separation of the different molecules.
The main separation mechanisms involved are size exclusion, ion exclusion and complex formation (or ligand exchange). Size exclusion refers to component classification via the molecule size; the larger the molecule, the faster it elutes through the resin bed.
The resin particles are porous materials (where the pore size can be controlled by the degree of cross linking) and the larger component is excluded from the smallest pores by steric repulsion. A typical example is the sucrose purification in beet molasses separation; sucrose is a disaccharide and therefore elutes in front of monosaccharides (glucose and fructose) or betaine.
Ion exclusion is a repulsion of any charged component either positive or negative. The resin matrix always has a so-called fixed ion and counter-ion (for electroneutrality). This structure will prevent the access of any other ions into the resin bead and therefore, these charged components will find their way out from the stationary phase through the void volume between the resin particles. Beet molasses separation can be used as an example in this case as well: salts (Na+, K+, SO42- and so on) are excluded from the resin beads and they elute from the separation column first.
Complex formation refers to temporary bonds which are formed between the resin counter-ion and some component in the feed material. HFCS or glucose-fructose separation is very well known example of this phenomenon: the fructose molecule makes a stronger complex with the Ca2+ counter-ion in the resin and it is thus retarded and separated from the glucose which only forms a weak complex.
These three main mechanisms above can be used to design a chromatography separation and they may operate in the system simultaneously.
Any chromatographic system consists of three important elements: the stationary phase (resin), the separation unit (which includes the resin column, eluent feed & collection system, detector and control unit) and the plant operators running the system. All of these are needed for optimum and successful chromatographic separation.
CURRENT INDUSTRIAL APPLICATIONS
Chromatography has been used in some industrial applications for many years and it finds new applications in several evolving processes. This is because of the many different mechanisms (see above) and the development of new resins, allowing an efficient recovery of molecules even in complex systems. Chromatography is an environmental friendly process (compared to for example solvent extraction) and may allow a recycle of the side fractions. In some cases, one chromatography system can produce more than just one product fraction.
Finex serves customers globally. The following is a list of some typical industrial applications
- HFCS manufacturing
- Resin particle size from 220 µm to 350 µm, with cross linking levels of 5,5% to 8%; always in Ca2+form
- Crystalline fructose
- Ca2+ form resin, designed to produce very high purity for fructose
- Beet molasses separation
- Resin particle size from 280 µm to 350 µm
- Resin operates in K+/Na+ form and can be delivered in both Na+ or K+ form
- Xylose recovery
- Tailor made, proprietary resins for xylose separation
- Organic acids
- Evolving area where the exact resin specification depends on the organic acid and particularly on the impurity profile
- Possibility for acid recycle in acid hydrolysis processes
- Rare sugars
- Several different proprietary resins for the difficult recovery of valuable molecules from a complex mixture of components
- Lactose free milk
- Lactose removal in a proprietary process
- Amino acids
- Proprietary resins either for eluent or adsorption chromatography
Our manufacturing method allows a free adjustment of the resin particle size (range from 220 µm to 500 µm) and very accurate control of the level of cross linking. The ion form is sometimes dependent on the ion content of the feed material but sometimes it can be used as an additional control parameter as well. Although Finex can serve existing clients for refill or make-up resins – in which case we meet the existing resin specification – we typically develop the optimum resin characteristics together with the client. This is especially the case in applications where the existing resin is not necessarily the optimum product and the client wishes to improve the process efficiency and/or decrease the operational costs. This development work is carried out under strict confidentiality which is also expressed above in the application list.
It is important to remember the triangle mentioned above: any successful chromatography process depends on the resin, the separation system and the operators running it. Even the best tailor-made resin can fail to produce the optimum results if the column design does not allow the benefits of the resin to be realised.
The particle size is a typical example of this challenge: the smaller the resin particle size, the more efficient the separation (see figure below). For an existing system, the increased pressure drop should be taken into account. It is important that the chromatographic separation process is fully understood by the operators otherwise the full benefit of the resin and the process may not be realized. If desired, Finex can offer basic training and familiarisation with the operation of the chromatographic system.