Studies on the application of photochemical reactions in a flow injection system. Part 2. Simultaneous determination of iron(II) and iron(III) based on the photoreduction of the iron(III)–phenanthroline complex

Abstract

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.