New lab system allows macromolecule analysis

PANalytical has added a new focusing mirror to its range of PreFIX optics that for the first time, can analyse macromolecules using a standard, laboratory-based XRD system, rather than on a synchrotron beam line or a single crystal diffractometer.

Emphasis on the research and development of macromolecules - especially in areas such as protein pharmaceutics - has increased in recent years. Many macromolecular materials have traditionally been considered 'difficult' for X-ray diffraction because of their weak scattering characteristics and small sample volumes.

Often, however, a lot of effort is put in growing crystals of sufficient size for the single crystal diffractometer. In the cases where this was impossible a synchrotron beam line was needed for recording power patterns.

The power of X-Ray diffraction as the only analytical technique capable of distinguishing crystalline phases is well recognised. It has long been considered a tool best suited to the laboratory because of its low measurement speed and need for specialist knowledge.

PANalytical's addition allows transmission diffraction experiments to be carried out on macromolecules, such as proteins, using the company's X'Pert PRO MPD X-ray diffraction system.

Experiments on hen egg white lysozyme using this system set-up gave cell parameters in good agreement with data obtained from single crystal measurements.

X-ray diffraction involves the qualitative and quantitative determination of the crystalline phases that describe the spatial arrangement of chemical elements in a crystalline solid.

The power of X-ray powder diffraction in distinguishing crystalline phases is beyond dispute.

By offering researchers the capacity to pre-screen and investigate protein-based medicines within the laboratory, use of the new mirror in combination with the X'Celerator detector represents a real technical advance.

As a PreFIX optic, the focusing mirror is interchangeable with all other available incident optics for the X'Pert PRO MPD without the need for any re-alignment.

From a technical perspective, its use means that the size of the capillary tube no longer governs angular resolution, and peaks narrower than 0.05 degrees can be resolved easily.

More recently, new generation instruments (such as CubiX FAST with X'Celerator detector) meet the throughput requirements for production control.

As a result, laboratory researchers can take full advantage of XRD analysis to improve product quality and optimise energy consumption.