A DETERMINATION OF MAGNESIUM BY FLAME AAS

1 The sample is vaporised in an air-acetylene flame magnesium compounds are atomised and the magnesium atoms thus formed absorb radiation from a hollow cathode lamp. The absorbance is measured at a wavelength of 285.2 nm. 

1 This procedure yieids a standard curve that is iinear up to approximateiy 0.5 mg/L 

2 The detection limit is approximately 0.8 mg/L in the digest The determination limit is approximately 2.4 mg/L (5-16 mmol/kg in the dried piant material). 

1 Since Mg atoms are easily captured in the flame into poorly dissociating compounds, in particular with phosphate and aluminium, a releasing agent like lanthanum must be added. 

1 The reproducibility of determinations by this procedure should give, at reasonable control and thorough sample preparation, a coefficient of variation within 7 % + 5 mmol/kg. 

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