Lead Analysis Lead in solution may be readily determined by atomic absorption spectroscopy. The method is applicable to drinking, surface, and saline waters, wastewater, extracts, industrial waste, soils, sludge, sediments, solid wastes, air samples, dust wipes, paint chips, and any other solid wastes. A sample is aspirated and atomized in a flame. A light beam from a hollow cathode lamp is directed through the flame into a monochromator, and onto a detector, that measures the amount of absorbed light.
Absorption depends upon the presence of free unexcited ground-state atoms in the flame.
Because the wavelength of the light beam is characteristic of only the metal being determined, the light energy absorbed by the flame is a measure of the concentration of the lead in the sample. When using the furnace technique in conjunction with an atomic absorption spectrophotometer, a representative aliquot of a sample is placed in the graphite tube in the furnace, evaporated to dryness, charred, and atomized. As a greater percentage of available analyte atoms is vaporized and dissociated for absorption in the tube rather than the flame, the use of smaller sample volumes or detection of lower concentrations of elements is possible. Radiation from a given excited element is passed through the vapor containing ground-state atoms of that element. The intensity of the transmitted radiation decreases in proportion to the amount of the ground-state element in the vapor.