Determination of oligoelements in wheat

Ion chromatography (IC) is proposed as an accurate method to determine alkaline and alkaline-earth metals present in wheat. Atomic absorption spectrometry (AAS) has been used to characterise heavy metals in wheat. Both procedures have been validated by analysing a certified sample obtained from the National Institute of Standard and Technology. Several wheat samples of known origin, variety and crop year have been analysed to determine the content of lithium, sodium, potassium, magnesium and calcium by means of IC. The amount of barium(II), iron(III), manganese(II), nickel(II), cobalt(II), copper(II), lead(II) and zinc(II) has been determined by using AAS. Trace quantities (up to 0.5 mg l−1) of alkaline and alkaline-earth metals have also been detected by IC. The resulting composition of the different samples have been used to assess species, origin and variety of the examined wheat.