MICROWAVE MUFFLE FURNACE ASSISTED DECOMPOSITION OF VEGETABLE SAMPLES FOR FLAME ATOMIC SPECTROMETRIC DETERMINATION OF CA, MG, K, FE, MN AND ZN

Calcium, magnesium, potassium, iron, manganese and zinc can be accurately determined in vegetable samples by flame atomic absorption and flame emission spectrophotometry after a previous dry ashing of the sample in a microwave muffle furnace. This treatment is carried out in 45 min using a new accessory developed by us to obtain high temperatures on a domestic microwave oven. Sample ashes, obtained in the muffle, are diluted with nitric acid and the obtained slurry is introduced directly into an air-C2H2 flame for the analysis of Fe, Mn, and Zn, or injected into a double-channel FIA manifold to determine Ca, Mg and K. The obtained results agree with those certified and also with those obtained by a previous dry ashing in a conventional muffle furnace and they are more precise for all the determined elements.