Rapid determination of Cd in flour by electrothermal AAS using the slurry technique

Abstract

A rapid and simple method for the determination of Cd in rice flour using slurry sampling electrothermal atomic absorption spectrometry (AAS) is described. The weighed rice flour is suspended in a viscous colloidal solution of 3.0% boiled tapioca flour which contains 0.1% of Triton X-100. Up to 14% of rice flour can be added to make the slurry sample. The slurry was stable for at least two hours. Palladium was used to allow the pyrolysis at 700°C. Oxygen ashing is not necessary at a low percentage of flour, whereas it can help prevent the quick buildup of carbon residue at high percentages. Commercial flour samples were analyzed and the results compared with those obtained from wet-digestion prior to electrothermal AAS determination. The repeatability of the method using 5-14% flour slurry was 3-10% and the detection limit was 0.28 ng/g Cd. The proposed method is simple, rapid, precise, accurate, and requires only a short preparation time and small amounts of reagents.