Ultrastructure of whewellite kidney stones: electron-analytical investigation

The investigation of the degree of interpenetration between the two component phases of whewellite kidney stones, the protein matrix and calcium oxalate monohydrate crystallites, is extended by a technique of microchemical analysis, employing X-ray photoelectron spectroscopy (XPS). The technique involves determining the surface elemental (hence chemical) composition of fractured whewellite stones. Comparison with the bulk composition of about 95% COM and 5% matrix yielded information on the fracture path, hence on the spatial distribution of the two phases. The results showed large increases in matrix signal upon fracture, confirming that the minor phase, matrix, which is expected to provide an easy path for fracture, pervades the structure down to the level of individual crystallites.