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 graphite furnace atomic absorption spectrometry. Samples were digested by means 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 concentrations of the elements studied in the bulgur samples obtained by the four digestion methods are inconsistent in limits of standard deviations. It was found that aluminum sulfate (4 mug/10 mul sample) added to the samples acted as a modifier, improving the signal shape and increasing the stability of slurries obtained from digestion procedures.