GFAAS Determination of Lead in Edible Oil with Micro-emulsion Injection

The micro-emulsion of sample of edible oil was prepared and introduced directly into the instrument, the content of lead was determined by GFAAS. The Zeeman effect was applied to eliminate the interference of background, NH4H2PO4 was used as matrix modifier, and temperatures for ashing and atomization were set at 500 ℃ and 1 800 ℃ respectively. Linear relationship between values of absorbance and mass concentration of lead was obtained in the range within 100 μg·L-1, with detection limit (3s) of 2.18 pg. The proposed method was used in the analysis of 5 samples of edible oil, values of recovery found by standard addition method were in the range of 89.8%-110%, and values of RSD (n=6) found were in the range of 3.4%-7.1%.