A valid method based on heat-assisted slurry sampling graphic furnace atomic absorption spectrometry
(HASS-GFAAS) was developed for the accurate determination of trace Pb in food standard reference
materials (SRMs). The HASS technique significantly improved Pb recovery and precision compared to
conventional slurry sampling techniques. The optimized HASS procedure was performed as follows:
first, the sample (particle size 150 mm) was diluted with 0.05% (v/v) Triton X-100 containing 2% HNO3
and 1% H2O2 followed by heating for 20 min at 120 8C on a heating block. Next, the obtained slurry was
sonicated in an autosampler cup, and finally, the slurry was introduced into a graphite tube and analyzed
by the GFAAS with a Pb electrodeless discharge lamp (EDL). Calibration with aqueous standard solutions
was used for Pb determination in food samples. The characteristic mass and limit of detection for Pb
based on the integrated absorbance for a 2% (m/v) sample were 12 0.6 pg and 0.003 mg kg1
,
respectively. The accuracy (95.1–102% recovery) and good precision (0.1–3.6%) of this procedure are
illustrated by the results obtained for the 12 food reference materials. The proposed method is suitable for
determination of trace Pb in solid food samples.