In analytical chemistry, ashing is the process of mineralization for preconcentration of trace substances prior to chemical analysis. Ash is the name given to all non-aqueous residue that remains after a sample is burned, which consists mostly of metal oxides.
Ash is one of the components in the proximate analysis of biological materials, consisting mainly of salty, inorganic constituents. It includes metal salts which are important for processes requiring ions such as Na+ (Sodium), K+ (Potassium), and Ca2+ (Calcium). It also includes trace minerals which are required for unique molecules, such as chlorophyll and hemoglobin.
- Typical honey analysis
In this example the ash would include all the minerals in honey.
- Oxides, e.g. Al2O3, CaO, Fe2O3, MgO, MnO, P2O5, K2O, SiO2
- CO3: Na2CO3 (soda ash), K2CO3 (potash)
- HCO3, e.g. NaHCO3 (baking soda)
- SO4: sulfate ash according to Ph. Eur.