Electrothermal Vaporisation System Including In Situ Digestion for the Direct Determination of Lead in Botanical Samples by Inductively Coupled Plasma Atomic Emission Spectrometry

A new approach to in situ solid sample digestion, subsequent vaporisation and introduction into an inductively coupled plasma, was developed for the direct determination of lead by atomic emission spectrometry. A powdered sample was mixed with diammonium hydrogenphosphate and the mixture was weighed in a sample cuvette made of tungsten. The cuvette was then placed on a tungsten boat furnace (TBF) and tetramethylammonium hydroxide solution was added to the mixture. After the in situ wet digestion was completed and the excess reagents were evaporated by the resistance heating of the TBF, the analyte in the sample cuvette was vaporised and introduced into the plasma. The solid samples were analysed by using a calibration curve prepared from the aqueous standard solutions. In this communication, system characterisation with lead and its analytical results in several biological samples are described.