Flow-injection simultaneous determination of copper and iron in patient sera with 2-(5-bromo-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)aniline and its application to disease diagnosis Original Research Article

New 20 and 30 mm light path length twin flow-cells were designed for the simultaneous flow-injection spectrophotometric determination of trace amounts of copper and iron in patients sera. Hence, utilization of the twin flow-cell enabled the sensitive determinations. Copper and iron can be determined simultaneously and rapidly at 580 and 710 nm using water-soluble reagent 5-Br-PSAA. The limits of detections (S/N=3) with the 20 mm path length flow-cell were 0.39 μg l−1 for copper and 0.20 μg l−1 for iron. The relative standard deviations (n=10) were 0.81% for 20 μg l−1 copper and 0.52% for 20 μg l−1 iron. Copper and iron in five kinds of control sera were determined by the proposed method and ICP–AES. The method was applied to the determination of copper and iron in patients sera and disease diagnosis. As the sensitivity of the proposed FI system was excellent, the amount of serum sample consumed in the pretreatment was small.