A DETERMINATION OF ALUMINIUM BY SPECTROPHOTOMETRY

1 Aluminium ions form - in weakly acid medium and in the presence of a polycyclic ketoamine - an extremely stable, red-coloured complex with Eriochrome Cyanine R. The intensity of the red-coloured complex can be measured with a spectrophotometer at a wavelength of 595 nm. 

2 This determination may be carried out on digest 2.3 (microwave digestion with 

HNOj - HjOj - HF), digest 2.4 (digestion with HNO3 - - HF) and digest 2.7 

1 The procedure yields a standard cunre that is linear up to approximately 5 mg/L Al. 

2 The detection limit is approximately 20 pg/L in the digest. The determination limit is approximately 60 pg/L (3.0 mg/kg in the dried plant material). 

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