Ultrasonic extraction of iron from non-aqueous liquids

A novel procedure for the extraction of iron from predominately organic solvents has been described. An ultrasonic probe was used to create a microemulsion with a small quantity of nitric acid such that labile iron could be released into the aqueous vesicles and subsequently quantified after phase separation. The analytical and operational viability of using a simple colorimetric assay based on the coordination of aminothiol ligands (principally homocysteine) was evaluated in terms of signal sensitivity, selectivity and stability. The use of homocysteine provided a linear range for iron(III) from 9 microM to 50 microM with a corresponding limit of detection of 2 microM (based on 3s(b)). The effectiveness of the approach was assessed through the recovery of 0.3 ppm iron from a sample of commercial kerosene and the results compared with those obtained through attempting to quantify the iron under passive (ultrasonically silent) conditions.