DEVELOPMENT OF FLOW INJECTION ANALYSIS SYSTEM FOR DETERMINATION OF IRON(II) AND TOTAL IRON IN GROUND WATER

Jintana Klamtet

Abstract


A reversed flow injection spectrophotometric determination of iron(II) and total iron has
been carried out. It is based on the reaction between iron(II) and 4-(2-pyridylazo)-resorcinol
(PAR) in acetate buffer pH 9.0 yielding a yellowish-orange coloured complex with an
absorption maximum at 714 nm. The 50 μl of 5×10-4 mol L-1 PAR solution was injected
into a continuous flowing stream of 0.01 M HCl with an appropriate flow rate of 0.9 ml min-
1. Then, it was merged with sample solution and acetate buffer flowing at the rate of 2.2 and
2.4 ml min-1, respectively, and the sample zone was detected by spectrophotometer. The
optimum conditions of this system were determined. Two linear calibration curves over the
concentration range 0.05-3.00 mg L-1 of iron(II) and iron(III) solutions were obtained with
the regression equations A=0.176C+0.0128 (r2=0.9988) and A=0.1116C + 0.0018
(r2=0.9966), respectively. A detection limit (defined as 2σ) was 0.012 mg L-1 with a sample
throughput of 180 samples h-1. The relative standard deviation was 0..21% (n = 15) at the
3.00 mg L-1 Fe (II). The proposed method was successfully applied to the determination of
iron (II) and total iron in groundwater. Analytical results obtained by the proposed method
were in good agreement with those obtained by reference methods.

Keywords : Flow injection analysis, PAR,Iron


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