Hyphenating Multisyringe Flow Injection Lab-on-Valve Analysis with Atomic Fluorescence Spectrometry for On-Line Bead Injection Preconcentration and Determination of Trace Levels of Hydride-Forming Ele
详细信息 查看全文
- 作者：Xiangbao Long ; Manuel Miró ; Elo Harald Hansen ; José ; Manuel Estela ; Ví ; ctor Cerdà
- 刊名：Analytical Chemistry
- 出版年：2006
- 出版时间：December 15, 2006
- 年：2006
- 卷：78
- 期：24
- 页码：8290 - 8298
- 全文大小：126K
- 年卷期：v.78,no.24(December 15, 2006)
- ISSN：1520-6882
文摘
In this work the third generation of flow injection analysis,that is, the so-called micro-lab-on-valve (
LOV) approach,is proposed for the first time for the separation, preconcentration, and monitoring of metalloids as hyphenatedwith atomic fluorescence spectrometry (AFS). This wasmade feasible by interfacing the micromachined LOV-module with AFS by a multisyringe flowing stream network for on-line postcolumn derivatization of the eluateaimed at generation of hydride species. The potential ofthis new hyphenated technique for environmental assayswas ascertained via determination of ultratrace levelconcentrations of total inorganic arsenic in freshwater.Employing quantitative preoxidation of As(III) to As(V) inthe samples by means of permanganate, the methodinvolves preconcentration of arsenate at pH 10 on arenewable anion exchanger, namely, Q-Sepharose, packedin a LOV microcolumn. The analyte species is afterwardstripped out and concurrently prereduced by a 300 Leluent plug containing 6 mol L-1 HCl and 10% KI. Theeluate is downstream merged with a metered volume ofsodium tetrahydroborate (0.3% w/v) for generation ofarsine, which is subsequently quantified by AFS. The flowsystem facilitates on-column reduction of the retainedarsenic with no need for application of programmablestopped flow. Yet, the high concentration of reductant andextreme pH conditions for elution hinder the sorbent tobe reused due to gradual deactivation of the functionalmoieties, so that maximum benefit can be taken from theapplication of the bead renewable strategy. The proposedprocedure is characterized by a high tolerance to metalspecies and interfering hydride-forming elements. In fact,ratios of Se(IV) to As 
5000 and Sb(V) to As 500 aretolerated at the 10% interference level. Under the optimized experimental conditions, a detection limit (3
) of0.02 ng mL-1 As, a dynamic linear range of 0.05-2.0 ngmL-1 As (by tailoring the AFS gain), an enrichment factorof 8.8 for arsenate, and a precision better than 6.0% atthe 0.1 ng mL-1 level were obtained for the bead-injectionmode whenever the loading sample volume was affixedat 3.0 mL. The reliability and accuracy of the automatedprocedure was ascertained by determining total inorganicarsenic in both spiked environmental waters and certifiedreference materials of variable matrix complexity (TMDA-54.3 and ERM-CA010) at the low ng mL-1 level. Nosignificant differences were found between the experimental results and the certified values at a significancelevel of 0.05.
LOV) approach,is proposed for the first time for the separation, preconcentration, and monitoring of metalloids as hyphenatedwith atomic fluorescence spectrometry (AFS). This wasmade feasible by interfacing the micromachined LOV-module with AFS by a multisyringe flowing stream network for on-line postcolumn derivatization of the eluateaimed at generation of hydride species. The potential ofthis new hyphenated technique for environmental assayswas ascertained via determination of ultratrace levelconcentrations of total inorganic arsenic in freshwater.Employing quantitative preoxidation of As(III) to As(V) inthe samples by means of permanganate, the methodinvolves preconcentration of arsenate at pH 10 on arenewable anion exchanger, namely, Q-Sepharose, packedin a LOV microcolumn. The analyte species is afterwardstripped out and concurrently prereduced by a 300 Leluent plug containing 6 mol L-1 HCl and 10% KI. Theeluate is downstream merged with a metered volume ofsodium tetrahydroborate (0.3% w/v) for generation ofarsine, which is subsequently quantified by AFS. The flowsystem facilitates on-column reduction of the retainedarsenic with no need for application of programmablestopped flow. Yet, the high concentration of reductant andextreme pH conditions for elution hinder the sorbent tobe reused due to gradual deactivation of the functionalmoieties, so that maximum benefit can be taken from theapplication of the bead renewable strategy. The proposedprocedure is characterized by a high tolerance to metalspecies and interfering hydride-forming elements. In fact,ratios of Se(IV) to As 5000 and Sb(V) to As 500 aretolerated at the 10% interference level. Under the optimized experimental conditions, a detection limit (3) of0.02 ng mL-1 As, a dynamic linear range of 0.05-2.0 ngmL-1 As (by tailoring the AFS gain), an enrichment factorof 8.8 for arsenate, and a precision better than 6.0% atthe 0.1 ng mL-1 level were obtained for the bead-injectionmode whenever the loading sample volume was affixedat 3.0 mL. The reliability and accuracy of the automatedprocedure was ascertained by determining total inorganicarsenic in both spiked environmental waters and certifiedreference materials of variable matrix complexity (TMDA-54.3 and ERM-CA010) at the low ng mL-1 level. Nosignificant differences were found between the experimental results and the certified values at a significancelevel of 0.05.