Optical microscopy compared with electron microscop

Unfortunately, the price that is paid for the convenience and capability of fluorescence microscopy is that of a relatively poor spatial resolution when compared with electron or X-ray microscopy. The size of the smallest details on a sample that can still be resolved is known as the resolution of the miaoscope. In optical microscopy, this fundamental limitation is roughly equal to half the wavelength of the used light, which typically corresponds to about 250 nm for blue-green excitation light (500 nm). In modem high-end research microscopes, this resolution limit is not due to technical or design issues, but solely determined by this apparently fundamental law of nature. 

An unusually extensive battery of experimental techniques was brought to bear on these comparisons of enantiomers with their racemic mixtures and of diastereomers with each other. A very sensitive Langmuir trough was constructed for the project, with temperature control from 15 to 40°C. In addition to the familiar force/area isotherms, which were used to compare all systems, measurements of surface potentials, surface shear viscosities, and dynamic suface tensions (for hysteresis only) were made on several systems with specially designed apparatus. Several microscopic techniques, epi-fluorescence optical microscopy, scanning tunneling microscopy, and electron microscopy, were applied to films of stearoylserine methyl ester, the most extensively investigated surfactant. 

The various general microscopy techniques are listed and compared in Tables 6.6 and 6.7. Table 6.6 compares optical and electron microscope techniques, with the magnification, resolution. 

The range of applicability of the above theoretical approaches and numerical results can be estimated by comparing them with experimental results obtained, mostly, by direct optical microscope observation and for monodisperse polystyrene latex particles [8-10, 13, 14, 19, 21, 22, 34—36]. Several sets of experimental data have also been gathered using the AFM for latex [17, 20], colloid gold [62] or dendrimer suspensions [26]. One can also apply electron microscopy to determine particle... 

---