Determination of ultra-trace amounts of selenium(IV) by flow injection hydride generation atomic absorption spectrometry with on-line preconcentration by co-precipitation with lanthanum hydroxide. Part II. On-line addition of co-precipitating agent

摘要: A flow injection procedure for the determination of ultra-trace amounts selenium(IV) is described, which combines hydride generation atomic absorption spectrometry (HGAAS) with on-line preconcentration analyte by co-precipitation–dissolution in a filterless knotted Microline reactor. Based on previously published that requires off-line premixing sample and co-precipitating agent, present approach facilitates addition co-precipitant to time-based aspirated sample. The coprecipitating agent (lanthanum nitrate) are mixed merged an ammonium buffer solution pH 9.1, promotes precipitation quantitative collection inner walls incorporated SeIV preconcentrated coprecipitation generated lanthanum hydroxide precipitate subsequently eluted hydrochloric acid, allowing ensuing via generation. At different rates, i.e., 4.8, 6.4 8.8 ml min–1, enrichment factors 30, 40 46, respectively, were obtained at sampling frequency 33 samples h–1. detection limit (3s) was 0.005 µg l–1 rate min–1 precision (relative standard deviation) 0.5%(n= 11) 0.1 level.