Determination of vanadium by solid-phase spectrophotometry in a continuous flow system

A flow analysis method based on direct absorptiometric measurement in solid phase of the violet complex formed between V(V) and 5-Bromosalicylhydroxamic acid has been developed. The measurement is continuously performed at 555 nm, while the coloured species is being concentrated on-line on the beads of an anion exchanger packed into a flow-through cell. The sensing solid phase is regenerated after each measurement achieving a sampling frequency ranged between 10 to 15 h(-1) depending on the working conditions. The sensitivity of the method depended on the sample volume injected, being the detection limit 0.024 and 0.014 mu g mL(-1) for 2 and 5 mt, respectively. The method shows a good selectivity and has been applied to determination of V(V) in many different sample matrices namely mussel, oyster and toadstool tissues, petroleum crudes and water samples.