A laboratory-built flow injection analyzer is reported for monitoring the drinking water disinfectants silver (I) ion and iodine in water produced from NASA's water recovery system. This analyzer uses spectrophotometric detection with a custom made 10cm optical flow cell. Optimization and interference studies are discussed for the silver (I) ion configuration. Subsequent results using the silver (I) configuration with minor modifications and alternative reagents gave promising results for iodine determinations as well. The estimated MDL values for Ag(+) and I2 are 52μg L(-1) Ag(+) and 2μg L(-1) I2; the mean percent recoveries were 104% and 96.2% for Ag(+) and I2 respectfully; and percent relative standard deviations were estimated at 1.4% for Ag(+) and 5.7% for I2. The agreement of this potentially multifunctional analyzer to reference methods for each respective water disinfectant is measured using Bland-Altman analysis as well as more traditional estimates.
Keywords: Disinfectant; Flow analysis; Iodine; Silver ion.
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