We use FAA to quantify various elements. Flame Atomic Absorbance (FAA) relies on aspirating a sample and atomizing it in a flame. A light beam from a lamp is directed through the flame and into a monochoromator which focuses the detector on the wavelength of maximum absorption of the element. The amount of light absorbed by the flame is inversely proportional to the amount of that element in the sample. Metal ion concentrations of unknown samples are determined by comparison to an external or internal calibration (method of standard addition) of the instrument. The concentration of the metal(s) in the sample is typically expressed in terms of the original mass taken for the analysis (wt/wt or wt/Vol).