Study on Slurry Sampling Technique for the Determination of Trace Metals in Food by Electrothermal Atomic Absorption Spectrometry

The slurry sample introduction approach is a convenient method of solid sampling that allows the rapid and accurate determination of trace metals in foodstuffs by ETAAS. Since complex dissolution of the samples is avoided,sample handling is minimal and possible sources of contamination are reduced. Among which, preparation of suspension and optimization of the graphite furnace heating program are important. First, the samples are pulverized using homogenizer at speed lOOOOr/min. Ninety percent of the particles are less than 30um in diameter after a pulverizing period of 6min for vegetable, fruit and liver; 25min for beef and pork; 8min for cereals, which allow the preparation of stable slurries up to at least 10%. Second, suspensions are prepared in medium containing 0.15% agar as stabilizing agent, which stabilizing time is up to two days.