2.3.2. Graphite furnace atomic absorption spectrophotometry (GFAAS)
Samples were determined for Pb and Cd by wet digestion in a
closed digestion system (Teflon jar) using a mixture of concentrated
nitric acid and perchloric acid (10:1, v/v) at 110 8C overnight
until a clear solution was obtained. Pb and Cd from samples were
extracted into the chloroform layer by complexion with ammonium-1-pyrrolidine dithiocarbamate (APDC), then diluted with nitric
acid and minerals content was determined by GF-AAS (Varian,
Graphite Components, Part No. 63-100012-00, Germany) using a
standard addition method.