Knauer Offers New Separation Columns and Screening Services

Knauer, a Berlin, Germany-based manufacturer of scientific instruments for liquid chromatography systems and components, now offers three new chiral stationary phases (CSPs), including new separation columns, for the enantioseparation of chiral substances. The CSPs are typically applied in production or quality control of pharmaceuticals with chiral active ingredients. To select the optimal chiral column, the company also offers a screening service.

Classical high-performance liquid chromatography (HPLC) columns, such as C18, are usually not suitable when separation of enantiomers is desired because the molecules do not differ in physical properties except for their geometry, according to Knauer. A CSP preferentially allows the passage of one enantiomer and penalizes the passage of the other based on the molecular geometry of the surface modification, called a chiral selector. Thus, enantioselective columns are often an indispensable purification tool in pharmaceutical production processes because the synthesis of active ingredients is not always enantioselective enough to get the correct desired enantiomer. This has important implications in pharmaceutical production because two enantiomers of an active ingredient are likely to have different physiological effects, which is why only the enantiomer with the desired effect is allowed, according to Knauer.

The new columns, Eurospher II Chiral columns, are available in three modifications that cover most enantioseparation tasks and are used for analytical and preparative liquid chromatography. Eurospher II Chiral AM and OM are polysaccharide CSPs, consisting of a silica base coated with a chiral selector. The chiral selector is amylose-tris-(3,5-dimethylphenylcarbamate) for the Eurospher II Chiral AM CSP and cellulose-tris-(3,5-dimethylphenylcarbamate) for Eurospher II Chiral OM.

Both these CSPs cover a range of chiral separation tasks but are relatively delicate because the selector is just a coating. For example, some solvents that are typically used in other HPLC separations must be avoided completely, the company states.

The third CSP, Eurospher II Chiral NR, is much more stable because it is an immobilized brush-type phase. The stability of this column and its high capacity make it well-suited for preparative applications. At the same time, Eurospher II Chiral NR is not as versatile as its polysaccharide companions.

The three CSPs are available for normal phase and reversed phase mode.

Because most chiral separations are not predictable, Knauer also offers a screening service to find the best matching CSP for the desired chiral separation task in normal phase mode.

Source: Knauer