STUDIES ON THE APPLICATION OF PHOTOCHEMICAL-REACTIONS IN A FLOW-INJECTION SYSTEM .2. SIMULTANEOUS DETERMINATION OF IRON(II) AND IRON(III) BASED ON THE PHOTOREDUCTION OF THE IRON(III)-PHENANTHROLINE COMPLEX

An automated procedure for the simultaneous determination of iron(II) and iron(III) was developed, involving the use of a laboratory-built flow-through photochemical reactor in a flow injection system based on the photoreduction of the iron(III)-1,10-phenanthroline complex. Optimum analytical conditions were established. A 100 mm3 Sample injection gave linear working ranges of 0.1-120 ppm of iron(II) and 0.2-120 ppm of total iron. The sample throughput was 40-60 h-1. The proposed method was applied to the determination of iron(II) and iron(III) in synthetic mixtures of standard iron(ii) and iron(III) and the catalyst for synthetic ammonia manufacture.