The determination of trace amounts of tin by flow-injection hydride generation atomic-absorption spectrometry with on-line ion-exchange separation and preconcentration

摘要: A hydride generation atomic-absorption spectrometric (AAS) method with flow-injection (FI), aimed at developing a practical routine assay for the determination of tin in food digests, is described. In order to modify sample matrix and achieve optimized reproducible conditions reaction, analyte initially converted into its chlorostannate-complex thereby allowing it be separated preconcentrated on-line on an incorporated micro-column packed strongly basic anion exchanger subsequently eluted by diluted nitric acid under strictly controlled conditions. Optimum acidic FI AAS system was found 0.01-0.05M acid. At consumption 2.7-ml volume, aspirated time-based injection, procedure resulted enrichment factor 3.5 yielded detection limit 0.08 microg/l. (3sigma) sampling frequency 72/hr. The precision 2.5% rsd 10 level. Potential interferents, such as Ni(II), Co(II), Zn(II) Fe(III) could, Sn level microg/l., tolerated excess 1000 times without impairing assay, while 100-1000-fold Cu(II) decreased signal 10-15%. Recoveries range 94-102% were obtained canned digests spiked Sn.