FLOW-INJECTION FLAME ATOMIC-ABSORPTION SPECTROMETRY FOR SLURRY ATOMIZATION - DETERMINATION OF CALCIUM, MAGNESIUM, IRON, ZINC AND MANGANESE IN VEGETABLES

A flame atomic absorption spectrometric procedure for determining the iron, zinc, manganese. calcium and magnesium contents of slurries prep ared from vegetables is described. Samples were first submitted to a m ild calcination step and then suspensions were prepared and introduced into an air-acetylene flame using a simple flow-injection manifold. T he calibration for iron, zinc and manganese was carried out using eith er aqueous standards or a flow-injection sample-to-standard additions method applicable to suspensions. The calcium and magnesium contents w ere too high for the direct introduction of the slurries into the flam e and so an on-line dilution system was used. Excellent agreement was found between the results of the slurry-based procedures and those obt ained by an alternative method involving calcination and dissolution i n acid. The reliability of the approach was confirmed by analysing two certified reference materials.