Low-temperature, oxygen plasma etching (OPE) is a useful technique in electron-microscopic (EM) morphological studies of mineral-containing organic polymers and biological structures. OPE gently and cleanly etches away the organic matrix at the surface of the specimen, leaving behind oxides and salts of exposed mineral elements. X-ray photoelectron spectroscopy (XPS) is widely used for macroscopic chemical analysis of the surfaces of polymers and inorganic specimens. The XPS signal originates from a surface depth of less than 100 Å. Combined application of the three techniques, OPE, EM and XPS to dispersible, macroscopic specimens which are microscopically homogeneous should allow correlation of fine structural features with surface and subsurface chemical composition. The present, preliminary study explores this possibility on bacterial spores and cells. Further details, and similar studies on tissue culture cells will be reported elsewhere.
Expanding the solid-state landscape of fluconazole: combined application of solid-state NMR, X-ray diffraction and computational methods to uncover polymorphism in fluconazole solvates