USE OF A SEQUENTIAL INJECTION TECHNIQUE TO EVALUATE THE EFFECT OF MIXING CHAMBERS ON ZONE PENETRATION

The simple chemistry and fast rate of the complexation reaction betwee n tiron and iron(III) were used to evaluate the effect four mixing cha mbers of various volumes (1.2-4.0 mi) have on the degree and reproduci bility 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(LII) in mine waters i s proposed. Using a 1.2 mi mixing chamber placed before the detector, the method is able to analyse 24 samples per hour with an average rela tive standard deviation of 0.28%. The calibration graph is linear betw een 0 and 200 mg l(-1) with a 3 sigma detection limit of 0.03 mg l(-1) . (C) 1998 Elsevier Science B.V.