A sample holder for in-house X-ray powder diffraction studies of protein powders

A sample holder for handling samples of protein for in-house X-ray powder diffraction (XRPD) analysis has been made and tested on lysozyme. The use of an integrated pinhole reduced the background, and good signal-to-noise ratios were obtained from only 7 µl of sample, corresponding to approximately 2–3 mg of dry protein. The sample holder is further adaptable to X-ray absorption spectroscopy (XAS) measurements. Both XRPD and XAS at the Zn K-edge were tested with hexameric Zn insulin.