A Novel Sealed Cell with Microliter Cavities for Temperature Measurements of Solution Structure by Small-Angle X-Ray Scattering

A sample cell with increased efficiency compared to standard quartz capillaries for studying the structure of solutions by small-angle X-ray scattering (SAXS) has been developed and tested. The circular cross-section of the standard quartz capillary leads to a decrease in the effective aperture and the appearance of additional parasitic scattering. A special feature of the cell design is the presence of plane–parallel X-ray transparent windows, which provide a significant improvement in the signal-to-noise ratio of SAXS data compared to data obtained using standard imported capillaries. The cell design includes at least two identical microliter cavities for samples, which allows comparing the measured object with a reference solution in one experiment or using solutions with different chemical compositions (including concentrations). Test measurements for a standard capillary and the proposed cell were carried out, showing a significantly more isotropic scattering pattern when using the cell. Its advantages are the reusable cell design and replacement of imported products (quartz capillaries). The cell has been successfully tested for studying crystallization solutions of potassium dihydrophosphate and lysozyme protein at different temperatures.