Use of a sequential injection technique to evaluate the effect of mixing chambers on zone penetration Original Research Article

The simple chemistry and fast rate of the complexation reaction between tiron and iron(III) were used to evaluate the effect four mixing chambers of various volumes (1.2–4.0 ml) have on the degree and reproducibility of zone penetration within a sequential injection (SI) system. As a consequence of this investigation a fully computerised SI system for the spectrophotometric determination of iron(III) in mine waters is proposed. Using a 1.2 ml mixing chamber placed before the detector, the method is able to analyse 24 samples per hour with an average relative standard deviation of 0.28%. The calibration graph is linear between 0 and 200 mg l−1 with a 3σ detection limit of 0.03 mg l−1.