Atomic methods require that the sample consist of individual gas phase atoms or gas phase atomic ions. With rare exceptions, this is not the form in which we obtain samples. If we are interested in analyzing seawater for the concentration of sodium, we need to find a way to convert the solution of aqueous sodium ions, Na + ( aq) , into gas phase sodium atoms, Na (g) , or gas phase sodium ions, Na + (g) . The process by which this happens is called atomization and requires a source of thermal energy. Examples of atomization methods include the use of flames, resistive heating, plasmas, and electric arcs and sparks. More details on specific atomization methods appear in the chapters that follow.