Wikipedia
Microincineration is a technique to determine the manner and distribution of mineral elements, e.g., calcium (Ca), potassium (K), sodium (Na), magnesium (Mg), iron (Fe), silica (Si), etc., in biological cells, biological tissues and organs. Slide prepatation of tissues can be used. The organic matter is vaporized by heating and nature and position of mineral ash is determined microscopically. Aqueous or cryo-EM fixed tissue materials can also be examined under transmission and scanning electron microscopy (TEM & SEM). The ashing procedure produces cellular oxidized-residues rich in Na2O, CaO, MgO, Fe2O3, SiO2, Ca(PO4)2, Mg(PO4)2, etc., which are detected by X-ray microanalysis with 2-4 times sensitivity gained after incineration of sample, due to increased mineral concentration and reduced nonspecific background radiation.