MODEL RELEASED. Atomic absorption (AA) spectrometer being used for quality control analysis at a modern pharmaceuticals plant. Here, the technician is about to spray a quantity of the sample into the spectrometer's flame. AA spectroscopy is used in the detection of very small concentrations of elemental metals, the presence of which even in minute concentrations would be undesirable in pharmaceutical products. The technique is able to detect metals such as lead at sample concentration levels of one in a million million parts.