Instrumentation and specimen preparation for electron beam X-ray microanalysis of frozen hydrated bulk specimens.

A cooling chain for the handling of frozen hydrated bulk specimens is described. Use of this method permits the specimen to be kept fully hydrated. After quench freezing, the specimen is transferred to a freeze etch apparatus, freeze fractured, carbon coated and transferred onto the precooled cold stage of the SEM by means of an airlock. The specimen is examined in the secondary electron mode and analysed using an energy dispersive X-ray analyser. The midgut of Chironomus thummi larvae and frog skin epithelium were used to test the performance.