Flow Injection Spectrophotometric Determination of Total Iron in Fresh Waters using 1,10-Phenanthroline Reagent

A simple flow injection method is reported for the determination of total iron in fresh waters based on spectrophotometric detection of reddish orange iron (II)–1,10-phenanthroline complex measured at wavelength 510 nm. The system permits high throughput of 120 samples per hour. A linear calibration (r2 = 0.9981) graph was obtained over the concentration range 0.2-1.0 mg L-1 with relative standard deviation (n = 4) 0.6-1.0 %. The limit of detection (3s blank) was 0.01 mg L-1. The proposed method has been applied successfully for the determination of iron in fresh water samples and the results obtained (0.04 ± 0.003-0.09 ± 0.01 mg L-1) were in reasonable agreement with the results obtained using a spectrophotometric method (0.05±0.008-0.1±0.005 mg L-1) as the reference method.