A comparison of sample preparation procedures for the determination of iron and zinc in bulgur wheat by graphite furnace atomic absorption spectrometry

A comparison was made of different digestion methods for the determination of iron and zinc in two types of bulgur wheat prior to their analysis in gr aphite furnace atomic absorption spectrometry. Samples were digested by mea ns of acid treatment in room temperature, acid treatment at 60 degreesC in a water bath and in a microwave oven and by dry ashing in open air system. Except for microwave digestion, the samples proved to be unclear. The conce ntrations of the elements studied in the bulgur samples obtained by the fou r digestion methods are inconsistent in limits of standard deviations. It w as found that aluminum sulfate (4 mug/10 mul sample) added to the samples a cted as a modifier, improving the signal shape and increasing the stability of slurries obtained from digestion procedures.