| Summary: | 碩士 === 國立臺灣海洋大學 === 生物科技研究所 === 96 === In this study, a hydride generation-packed cold finger-atomic fluorescence spectrometer (HG-PCF-AFS) system was established, and the system will be settled on-board for monitoring the variation of arsenic speciation in-situ. The AFS has the better sensitivity than AAS (atomic absorption spectrometer), consequently the HG-PCF-AFS technique required less inlet sample volume, reaction reagent and measurement time.
Proposed hydride-active arsenic species in seawater were arsenite (AsIII), arsenate (AsV), methylarsonate (MA) and dimethylarsinate (DMA). Hydride products were AsH3 (either AsIII or AsV), MeAsH2 and Me2AsH, which were concentrated in PCF by liquid nitrogen (LN2) cooling. Subsequently took away the LN2 and raised PCF temperature resulted in a pseu-chromatogram in which AsH3, MeAsH2 and Me2AsH vaporized in order. Replicate measurement showed the retention times were kept within �b 0.07 min.
Four analytical modes namely TAs, iAs, AsIII and orgAs (for analyzing MA and DMA) were designed. Since the operation parameters were optimized, the spike experiments for TAs, iAs, AsIII, MA and DMA showed the matrix effect was negligible, and the absolute detection limits were 0.17, 0.02, 0.13, 0.23 and 0.26 ng, respectively. Assumed mass balance TAs = �韹s = iAs + MA + DMA were estimated by analyzing real seawater, and the difference between TAs and �韹s is insignificant.
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