Practical aspects of electron energy loss spectroscopy (EELS) in biology

Abstract

New commercially available electron microscopes accessories permit an easy Electron Energy Loss Spectroscopy (EELS) analysis with good sensitivity and accuracy. But EELS still remains a complex method whose potentiality is seldomly completely exploited. Beside nanoanalysis, several possibilities of producing new images are described. The scattering power image for beam-sensitive specimens, the separation of elastic and inelastic components and the mean free path ratio are among these possibilities. Mass thickness measurement for example can benefit a lot from these techniques. In the nanoanalysis field, a particular emphasis is given to the spectrum-image acquisition method. This method is very convenient to obtain chemical maps of different elements from the same area of the specimen. The background effects and the errors in its estimation are often underevaluated. This can provoke spurious effects in chemical maps. The spectrum-image offers several ways to avoid this inconveniency.