| Résumé | A spectrophotometric method for the determination of AlIII in hemodialysis water employing alizarin red S complexing agent in the presence of polyvinylpyrrolidone 40 surfactant is described. The complex, formed in pH 4.5 buffered media, is detected at 510 nm. Optimal concentrations of all reagents were investigated as well as the appropriate detection wavelength. A linear analytical curve in the range of 5.0-320 µg L-¹ was obtained, providing a limit of detection (3s, n = 7) of 2 µg L-¹ and quantification limit of 5 µg L-¹. Results were compared with those generated using inductively coupled plasma mass spectrometry (ICP-MS) as an independent technique and method validation was also demonstrated by analysis of AccuStandard certified reference material QCS‑02-R1-5, appropriately diluted to 10 µg L-¹. Equivalent results (t-test at a 95% confidence level) with a relative standard deviation of 4% were obtained. Real samples, spiked at a level of 10 µg L-¹ to conforme to Brazilian legislated limits, showed recoveries between 90-110%. The procedure is simple and fit-for-purpose with sufficient detection power to screen for Al at trace levels in hemodialysis water without pre-concentration of the samples. |
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