Abstract:

Objective: To compare the effects of different pretreatment methods on determination of the content of 6 metal elements in
rapeseed oil. Methods: 15 samples of rapeseed oil were pretreated by dry ashing and wet digestion methods and the content of 6 kinds of metal elements such as lead, cadmium, cuprum and iron was determined by flame atomic absorption spectrometry（FAAS）. Results: After dry ashing and wet digestion treatments, the difference in the content of Pb and Cu had no statistical significance（P >0.05）, but there was statistical significance in the difference in the content of Fe and Mn（P < 0.05）. R2 of each element was over 0.99. The recovery rates of standard addition with the dry ashing method and with the wet digestion method were 81.90%-107.45% and 99.90%-108.05% respectively and satisfied the requirements of trace analysis. By contrast, the difference in recovery rates of standard addition between dry ashing and wet digestion methods was statistically significant（P < 0.05）and the recovery rate of the method of wet digestion and FAAS was higher than that of the dry ashing method. Conclusion: The accurate measuring result could be obtained by both methods but the wet digestion method was superior to the dry ashing method.

Key words: pretreatment, rapeseed oil, metal elements, flame atomic absorption spectrometry