Determination of thorium with DBF-arsenaz by flow-injection analysis

A sensitive, selective, rapid, simple, and convenient method for the determination of thorium was developed. The method was based on the color reaction of thorium with DBF-arsenazo in a strong acidic medium (4 mol/L HCl). The flow-injection technique was used with an automated flow-injection analyzer. Beer's law was obeyed in the range of 0–1.4 μg/mL. The relative standard deviations were less than 1%.