Pb Analysis by Atomic Absorption

Introduction

Lead has been used in diverse applications since ancient times because it displays excellent workability due to its low melting point and its softness. In addition, due to its high density, it is used as a shielding material for blocking X-rays or γ-rays, as well as in lead glass. On the other hand, lead is hazardous to human health, its acute poisoning appears as anemia, neuralgia or neurological brain disorders. When lead is ingested orally, it is said that the body absorbs about 10% of the total amount. While most of that is expelled in the feces in the form of lead phosphate or lead carbonate, a portion enters the blood and adheres to the bones and soft tissues. In the past, lead was used in tap water pipes, however, since it was discovered that it dissolves in the slightly acidic solution produced in the presence of oxygen, lead is now being replaced with stainless steel and synthetic plastic, etc. in tap water plumbing. In addition, the tetraethyl lead that had been added to gasoline as an octane rating enhancing antiknock substance to suppress excessive combustion in automobile engines are now prohibited due to environmental pollution concerns. In recognition of the hazardous nature of lead, lead- free movements are accelerating in various industries. For example, the RoHS* directive bans the use of specified harmful substances in electrical and electronic products marketed in the EU from the 1st July 2006. The specified hazardous substances include organic halides (brominated flame retardants) and hazardous metals, including mercury, cadmium, hexavalent chromium, along with lead. Lead analysis is conducted in a variety of fields, including water quality-related analysis on tap water and wastewater, environmental-related analysis on underground water and soil, and quality management analysis on food and pharmaceutical and industrial products, etc. Introduced here are examples of lead analysis in soil using the flame method, and in plastic using the furnace method.

June 23, 2004 GMT