Determination of chromium and selenium in silkworm pupa by electrothermal atomic absorption spectrometry

A method was developed for the determination of chromium and selenium in silkworm pupa using electrothermal atomic absorption spectrometry.The use of chemical modifiers as well as their implications during the pyrolysis step was examined.The chemical modifiers that were studied were Ni,Pd,Mg.The effect of modifiers was studied and it was found that better results were achieved with addition of 1 mg/mL Ni(NO3)2.The developed method was applied to the determination of chromium and selenium in silkworm pupa,which was digested with a HNO3+HClO4 in a triangle bottle.The repeatability of the method was less than 4.0% as RSD(%).Recoveries were estimated to be 96.8%～105.3% for Cr,92.1%～108.8% for Se.The linear ranges of Cr and Se were 0～10.0 μg/L,0～40.0 μg/L,respectively.The limit of detection for Cr was 1.22 μg/L,The limit of detection for Se was 1.86 μg/L.This method is simple,accurate and highly specific.The method was applied to silkworm pupa and the Cr,Se contents were found to be 1.821±0.073 ng/g,0.458±0.014 ng/g,respectively.This method can be used for the determination of Cr,Se in usual food.