An in-situ dielectric barrier discharge trap for ultrasensitive arsenic determination by atomic fluorescence spectrometry

Authors: QI, YUEHAN - Chinese Academy Of Agricultural Sciences; MAO, XUEFEI - Chinese Academy Of Agricultural Sciences; LIU, JIXIN - Chinese Academy Of Agricultural Sciences; NA, XING - Chinese Academy Of Agricultural Sciences; Chen, Guoying; LIU, MEITONG - Chinese Academy Of Agricultural Sciences; ZHENG, CHUANGMU - Chinese Academy Of Agricultural Sciences; QIAN, YONGZHONG - Chinese Academy Of Agricultural Sciences

Submitted to: Analytical Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2018
Publication Date: 4/24/2018
Citation: Qi, Y., Mao, X., Liu, J., Na, X., Chen, G., Liu, M., Zheng, C., Qian, Y. 2018. An in-situ dielectric barrier discharge trap for ultrasensitive arsenic determination by atomic fluorescence spectrometry. Analytical Chemistry. 90:6332-6338. https://doi.org/10.1021/acs.analchem.8b01199.
DOI: https://doi.org/10.1021/acs.analchem.8b01199

Interpretive Summary: The mechanisms of arsenic gas phase enrichment (GPE) by dielectric barrier discharge (DBD) was investigated. It proved for the first time that oxides, atoms and atom clusters are the species involved in DBD trapping, release, and transportation to the atomic fluorescence spectrometer (AFS), respectively. A novel DBD trap was re-designed accordingly as in-situ GPE approach. After trapping, sweeping, and releasing, 2.8 pg detection limit and 4-fold sensitivity enhancement were achieved in ~10 s sampling. Linear response and quantitative recoveries were achieved for tap, river, lake, and sea water samples. Validation was performed using certified reference materials.

Technical Abstract: The mechanisms of arsenic gas phase enrichment (GPE) by dielectric barrier discharge (DBD) was investigated via X-ray photoelectron spectroscopy (XPS), in-situ fiber optic spectrometer (FOS), etc. It proved for the first time that the arsenic species during DBD trapping, release, and transportation to the atomic fluorescence spectrometer (AFS) are probably oxides, atoms and atom clusters, respectively. Accordingly, a novel in-situ DBD trap as a GPE approach was re-designed using three-concentric quartz tube design and a modified gas line system. After trapping by O2 at 9.2 kV, sweeping for 180 s and releasing by H2 at 9.5 kV, 2.8 pg detection limit (LOD) was achieved without extra pre-concentration (sampling volume = 2 mL), as well as 4-fold enhancement in absolute sensitivity and ~10 s sampling time. The linearity reached R2 > 0.998 in the 0.1 – 8 µg/L range. The mean spiked recoveries for tap, river, lake, and sea water samples were 100% – 106%; and the measurements of the CRMs were in good agreement with the certified values. In-situ DBD trap is also suitable to AAS or OES for fast and on-site determination of multi-elements.