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A New Flow Injection and Sequential Injection Systems with Spectrophotometric Detections for Determination Magnesium Ion

Khdeeja Jabbar Ali and Fatima Fahim Abd

This research includes the design flow injection and sequential injection systems for determining magnesium ion containing valve is designed locally. The FIA and SIA systems based on the reaction of magnesium with Eriochrome Black T at pH (9-10.5) with an absorption maximum at 520 nm. Various parameters (physical and chemical) affecting the determination have been investigated such as flow rate, reaction coil, volume of reagent (Eriochrome Black T), volume of sample, concentration of Eriochrome Black T. The calibration curve was prepared and the dispersion coefficient, reproducibility, interferences and application were studied. Two methods, flow injection and sequential injection analysis were compared for determination of magnesium by Eriochrome Black T. The linear range was (1-15 mg/L), (0.05-15 mg/L) at sampling rate of 120, 100 sample per hour, the detection limits (0.0221 mg/L), (0.0096 mg/L) for FIA and SIA, respectively. Relative standard deviations for (15 mg/L), n = 3 were found (0.0823% for FIA and 0.1221% for SIA). Dispersion coefficient was also measured for the two methods.