HG-AFS Determination of Lead in Cassava and Its Fermentation Product-Alcohol

A method for determination of lead in cassava and its fermentation products (especially alcohol produced by fermentation of cassava) by HG-AFS was proposed.Cassava sample was digested with HNO3+HClO4(4+1) mixture in microwave sample digestor.The solution was evaporated to near dryness and the residue was taken up with HCl(1+19).Solutions of potassium ferricyanide and oxalic acid were added to eliminate interferences from Cu2+ and Fe3+,Mo(Ⅵ),Ni2+ respectively.Lead(Ⅱ) in the solution was then determined by HG-AFS under the optimized conditions.Linear relationship between values of peak area and mass concentration of Pb(Ⅱ) was obtained in the range of 1-280 μg·L-1,with detection limit (3S/N) of 5 μg·L-1 for cassava and 1 μg·L-1 for alcohol.Recovery of the method was tested by stanadrd addition method using samples of cassava and alcohol as matrixes,giving values of average recovery of 97.9% (for cassava) and 93.8% (for alcohol).Values of RSD′s (n=8) found from the analytical results of sample of cassava and alcohol were 2.68% and 2.14% respectively.