Know the purpose of your fly ash analysis. For example, fly ash can contain unburnt carbon, the major determinant of boiler combustion efficiency. If you are looking for unburned carbon, you are finding proof of substantial energy loss in the coal burning system. Other uses for fly ash analysis are academia and environmental research.
Verify that the sample is indeed fly ash, and make a record of the sample. Fly ash may come from waste incinerators, crematoriums, wood combustors, metal recycling plants and coal-burning power plants. Authentic fly ash is a fine, powdery material that generally appears to be a tan color. It's consistency seems like talcum powder. Fly ash is mostly composed of glass-like silica, and particles are usually spherically shaped when viewed under a microscope. Record any pertinent information about your sample before you begin (sample numbers, plant name, location and date) so you can keep your records accurate, or acquire additional samples if needed.
Use laser-induced breakdown spectroscopy (LIBS) to detect most of the components in the fly ash. According to Andor Technology, LIBS is a useful method for determining elemental composition of solids like fly ash. Andor Technologys also says a great benefit of using the LIBS technique is that very little or no sample preparation is needed, and LIBS can be used on very small samples. LIBS works using a short laser pulse that is focused on the fly ash sample, to create a plasma plume. Plasma plume emission is collected by a lens, or fiber optics, and then analyzed by the spectrograph, for spectral lines. These atomic spectral lines can be used to determine the elemental composition of your sample. Usually, plume emission is collected at a distance from the sample. This reduces self-absorption and surface effects.
Record and report your findings to the proper audience. Your audience may be the EPA, a college or university, or a specific power plant attempting to verify its coal-burning efficiency.