Simultaneous Spectrophotometric Determination of Phosphate and Silicate by a Stopped-Flow Sequential Injection Method

Mas-torres, Francisca; Muñoz, Antonio; Estela, José Manuel; Cerdà, Vı́ctor

doi:10.1080/03067310008032682

Cited by 17 publications

(7 citation statements)

References 13 publications

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“…When compared to some previous works, using the same reaction [7,16,20], the proposed system presents some significantly better analytical features. The potential interference of silicate was successfully masked by the in-line addition of tartaric acid.…”

Section: Resultsmentioning

confidence: 87%

Spectrophotometric flow system using vanadomolybdophosphate detection chemistry and a liquid waveguide capillary cell for the determination of phosphate with improved sensitivity in surface and ground water samples

Neves

Souto

Tóth

et al. 2008

Talanta

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Orthophosphate reacts with molybdate in acidic medium to yield 12-molybdophosphoric heteropolyacid; subsequently, detection is undertaken either on the molybdophosphate reduction product (molybdenum blue method) or on the yellow vanadomolybdate complex [2,5,6]. The molybdenum blue method became broadly used due to its higher sensitivity and lower susceptibility to interferences [4,7,8], than the vanadophosphomolybdate method. Nevertheless, the low concentration levels imposed by legislation are difficult to achieve. Therefore, the development of new methodologies capable of monitoring trace phosphate levels in environmental samples with adequate precision, has gained importance [9]. Flow injection analysis (FIA) is a widespread and well established approach to determine phosphorus. In fact, the first publication on FIA is dedicated to phosphate determination [10] and discusses both the yellow vanadomolybdate and the molybdenum blue method. Compared to the blue molybdenum method, the yellow vanadomolybdate analytical procedure can present some advantages that make it more suitable for flow systems: (i) the use of a single reagent mixture with extended stability makes the method suitable for field portable applications and for unattended operation in water monitoring [11,12] and (ii) the formation of a fine precipitate, accompanying the development of the blue colour, does not occur. However, maybe because of its limited sensitiv

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Section: Resultsmentioning

confidence: 87%

Spectrophotometric flow system using vanadomolybdophosphate detection chemistry and a liquid waveguide capillary cell for the determination of phosphate with improved sensitivity in surface and ground water samples

Neves

Souto

Tóth

et al. 2008

Talanta

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“…Spectrophotometry was the most widely used method of detection, although there were also quite a few methods that involved electrochemical detection. Almost 20% each of the listed references, described the determination of nitrite [67,96,107,118,116,117,132,131,140,155] and phosphate [52,77,107,120,119,135,134,[140][141][142]. For monitoring aquatic media, it is important not only the determination of these anions individually, but also the ratio…”

Section: Changes In Oxidation Statementioning

confidence: 99%

“…The determination of silicate and phosphate are often described together [120,119,141] because detection of both involves similar colorimetric reaction.…”

Section: Metals Determinationmentioning

confidence: 99%

A review on sequential injection methods for water analysis

Mesquita

Rangel

2009

Analytica Chimica Acta

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The development of fast, automatic and less expensive methods of analysis has always been the main aim of flow methodologies. The search for new procedures that still maintain the reliability and accuracy of the reference procedures is an ever growing challenge. New requirements are continually added to analytical methodologies, such as lower consumption of samples and reagents, miniaturisation and portability of the equipment, computer interfaces for full decision systems and so on. Therefore, the development of flow methodologies meeting the extra requirements of water analysis is a challenging work. Sequential injection analysis (SIA) presents a set of characteristics that make it highly suitable for water analysis. With sequential injection analysis, most routine determinations in waters can be performed more quickly with much lower reagent consumption when compared to reference procedures. Additionally, SIA can be a valuable tool for analyte speciation and multiparametric analysis. This paper critically reviews the overall work in this area.

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“…For a lake and a tap water sample, Wu and Růžička [13] applied the kinetic stopped flow measurement mode, which can also contribute to the reduction of sample matrix effects in the applied Lab-on-Valve SIA mode. The same stopped flow strategy was used earlier by Mas-Torres et al [14], to simultaneously measure phosphate and silicate in waste waters, although under certain conditions the mutual interference of the two analytes could be detected. Another interesting approach presented by the same research group [18] was based on the use of the sample solution as carrier to detect multiplicative interferences in the determination.…”

Section: Introductionmentioning

confidence: 99%

“…SIA methods have recognised merits of robustness and versatility enabling the possibility to change the determination conditions without physical reconfiguration of the manifolds. In this scenario, several SIA methods have been reported for the spectrophotometric determination of phosphate [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] as listed in Table 1. However, these methods were generally developed for the application to a single type of water (even when other samples were also used).…”

Section: Introductionmentioning

confidence: 99%

Development of a flow method for the determination of phosphate in estuarine and freshwaters—Comparison of flow cells in spectrophotometric sequential injection analysis

Mesquita¹,

Ferreira²,

Tóth³

et al. 2011

Analytica Chimica Acta

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A sequential injection system with dual analytical line was developed and applied in the comparison of two different detection systems viz; a conventional spectrophotometer with a commercial flow cell, and a multi-reflective flow cell coupled with a photometric detector under the same experimental conditions. The study was based on the spectrophotometric determination of phosphate using the molybdenum-blue chemistry. The two alternative flow cells were compared in terms of their response to variation of sample salinity, susceptibility to interferences and to refractive index changes. The developed method was applied to the determination of phosphate in natural waters (estuarine, river, well and ground waters). The achieved detection limit (0.007 μM PO(4)(3-)) is consistent with the requirement of the target water samples, and a wide quantification range (0.024-9.5 μM) was achieved using both detection systems.

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Simultaneous Spectrophotometric Determination of Phosphate and Silicate by a Stopped-Flow Sequential Injection Method

Cited by 17 publications

References 13 publications

Spectrophotometric flow system using vanadomolybdophosphate detection chemistry and a liquid waveguide capillary cell for the determination of phosphate with improved sensitivity in surface and ground water samples

Spectrophotometric flow system using vanadomolybdophosphate detection chemistry and a liquid waveguide capillary cell for the determination of phosphate with improved sensitivity in surface and ground water samples

A review on sequential injection methods for water analysis

Development of a flow method for the determination of phosphate in estuarine and freshwaters—Comparison of flow cells in spectrophotometric sequential injection analysis

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