X-ray microanalysis of epon sections after oxygen plasma microincineration

Dark-gold sections of osmium tetroxide-fixed, Epon-embedded brown adipose tissue before and after low-temperature oxygen plasma microincineration were examined using a high-resolution scanning transmission electron microscope and an energy-dispersive X-ray spectrometer. Microincineration produced ash patterns which were free of organic matrix, chlorine (from the Epon) and probably osmium (from the fixative). X-ray sensitivity was improved by a factor of 2-4 owing to decreased background, and sulphur, calcium and probably phosphorus were detected in the ash. Fidelity of the ash patterns permitted microanalytical spatial resolution of 0.1 micrometer or better. Oxygen plasma microincineration is thus shown to offer advantages for high resolution X-ray microanalysis of conventionally sectioned biological material. Its future application to shock-frozen, frozen-dried, unstained sections is indicated.