提出了用氢化物发生-原子荧光光谱法测定木薯干及其发酵产物(主要指用木薯干发酵所产生的酒精)中铅量的方法.其中木薯干样品系用硝酸-高氯酸(4+1)的混合酸在微波消解仪中作消解处理,将所得溶液蒸发至近干后,用盐酸(1+19)溶液溶解残渣.先后加入铁氰化钾溶液及草酸溶液分别消除铜(Ⅱ)及铁(Ⅲ)、钼(Ⅵ)、镍(Ⅱ)所引起的干扰.然后按所优选的条件用氢化物发生-原子荧光光谱法测定溶液中铅(Ⅱ)量.测得铅(Ⅱ)的质量浓度在1~280 μg·L-1范围内与相应的峰面积测量值之间呈线性关系,其检出限(3S/N)为5 μg·L-1(对木薯干样品)及1 μg·L-1(对酒精样品).以木薯干和酒精为基体添加标准溶液,木薯干和酒精的平均加标回收率分别为97.9%和93.8%,测定结果的相对标准偏差(n=8)依次为2.68%及2.14%.

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.