Determination of total iron as Fe(II) in multivitamins, haematinics and natural waters using a sequential injection (SIA) system

The determination of total iron in pharmaceutical products and natural waters as Fe(II) using a sequential injection system was investigated. A cadmium reductor consisting of cadmium granules was used to reduce Fe (III) to Fe (II). The Fe (II) was then determined (by its reaction with 1,10 Phenanthroline ) as a [Fe(phen)3 ] complex at 515 nm with a UV/Vis spectrophotometer. The linear range of the system is between 1 and 60 mg/l with a detection limit of 0.18 mg/l. The proposed system is suitable for the determination of total iron as Fe(II) in pharmaceutical products and natural waters at a rate of 24 samples/hour with a relative standard deviation of less than 2.5%. Statistical comparison between the proposed sequential injection (SIA) system, certified values and the standard methods (Inductively Coupled Plasma {ICP} and UV/Vis spectrophotometry) revealed that there is no significant difference at the 95% confidence level.