Detection of Arsenic(III) through Pulsed Laser-Induced Desorption/Ionization of Gold Nanoparticles on Cellulose Membranes

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• 作者：Cheng-I Weng ; Jin-Shun Cang ; Jia-Yaw Chang ; Tung-Ming Hsiung ; Binesh Unnikrishnan ; Yu-Lun Hung ; Yu-Ting Tseng ; Yu-Jia Li ; Yu-Wei Shen ; Chih-Ching Huang
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：March 18, 2014
• 年：2014
• 卷：86
• 期：6
• 页码：3167-3173
• 全文大小：379K
• 年卷期：v.86,no.6(March 18, 2014)
• ISSN：1520-6882

文摘

We have developed an assay based on gold nanoparticle-modified mixed cellulose ester membrane (Au NPs-MCEM) coupled with laser-induced desorption/ionization mass spectrometry (LDI-MS)-for the detection of arsenic(III) ions (arsenite, AsO₂^{鈥?/sup>) in aqueous solution. When the Au NPs reacted with lead ions (Pb2+) in alkaline solution (5 mM glycine鈥揘aOH, pH 12), Au鈥揚b complexes, PbO, and Pb(OH) were formed immediately on the Au NP surfaces. The Pb species reacted rapidly with subsequently added AsO₂鈥?/sup> to form PbOAs₂O₃, (PbO)₂As₂O₃, and/or (PbO)₃As₂O₃ shells (2鈥? nm) on the Au NPs鈥?surfaces. As a result, significant observable aggregation of the Au NPs occurred in the solution. This Pb2+/Au NP probe allowed the detection of AsO₂鈥?/sup> at concentrations as low as 0.6 渭M with high selectivity (at least 100-fold over other anions and metal ions). To further improve the sensitivity, we prepared Au NPs-MCEM for the LDI-MS-based detection of AsO₂鈥?/sup> ions. The intensity of the signal for the [Pb]+ ions in the mass spectra increased when the Au NPs-MCEM reacted with AsO₂鈥?/sup>; in contrast, the intensity of the signal for [Au]+ ions decreased. Accordingly, the [Pb]+/[Au]+ peak ratio increased upon increasing the AsO₂鈥?/sup> concentration over the range from 10 nM to 10 渭M. The limit of detection at a signal-to-noise ratio of 3 was 2.5 nM, far below the action level of As (133 nM, ca. 10 ppb) permitted by the US EPA for drinking water. Relative to other nanoparticle-based arsenic sensors, this approach is rapid, specific, and sensitive; in addition, it can be applied to the detection of AsO₂鈥?/sup> in natural water samples (in this case, streamwater, lake water, tap water, groundwater, and mineral water).}