Multicommutation in flow analysis. Part 5: Binary sampling for sequential spectrophotometric determination of ammonium and phosphate in plant digests

Kronka, Eloisa A.M.; Reis, Boaventura F.; Korn, Mauro; F̊, Henrique Bergamin

doi:10.1016/s0003-2670(96)00267-x

Cited by 31 publications

(13 citation statements)

References 12 publications

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“…Analytical procedures based on the multi-commutation process have been developed for analytes determination in matrices such as plant digest, [5,6] pharmaceutical formulations, [7,8] surface water, [9,10] lubricant oil, [11] biologic fluid, [12,13] alcoholic beverage, [14,15] and silage extract. [16,17] The procedures implemented based on the multi-commutation process have been employed as detection techniques: UV-Vis spectrophotometry, [18] potentiometry, [19,20] fluorimetry, [21,22] chemiluminescence, [23,24] and infrared spectrophotometry.…”

Section: Introductionmentioning

confidence: 99%

Multi‐commutation in Flow Analysis: A Versatile Tool for the Development of the Automatic Analytical Procedure Focused on the Reduction of Reagent Consumption

Lavorante

Feres

Reis

2006

Spectroscopy Letters

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In this work, a general view of multi-commutation in flow analysis process is presented. The manuscript comprises a comprehensive description of the basic manifolds designed to demonstrate the multi-commutation concept including the operational modes and the inherent features. A multi-function flow system with the ability to carry out three-operation modes without any hardware modification is also described. Intending to demonstrate the versatility of the flow system based on multi-commutation process, a set of experiments was designed comprising an in-line dilution and stopped flow approach. Standard solutions of iron and of orthophosphate were selected as models to demonstrate the analytical potential of the proposed system. The results obtained are presented and discussed.

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Section: Introductionmentioning

confidence: 99%

Multi‐commutation in Flow Analysis: A Versatile Tool for the Development of the Automatic Analytical Procedure Focused on the Reduction of Reagent Consumption

Lavorante

Feres

Reis

2006

Spectroscopy Letters

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“…15,16 On another hand, a flow system based on a multicommutation approach can handle several solutions using a single pumping channel. 17,18 A decrease in reagent consumption is another advantage that is easily achieved by employing a multicommutation approach. 19 In this work, we intend to develop an automatic flow procedure for the simultaneous spectrophotometric determination of nonstructural carbohydrates and reducing sugar in forage material by employing a flow system based on a multicommutation approach.…”

Section: Introductionmentioning

confidence: 99%

Automatic Procedure Exploiting Multicommutation in Flow Analysis for Simultaneous Spectrophotometric Determination of Nonstructural Carbohydrates and Reducing Sugar in Forage Materials

2003

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A multicommutated flow procedure for simultaneous spectrophotometric determination of nonstructural carbohydrates and reducing sugar in forage materials is proposed. Determination of both analytes was based on the neucroine method after acid hydrolysis of nonstructural carbohydrates. Results for both analytes presented the following features: no significant difference at 90% confidence level when compared with reference method, linear response between 0.2 to 0.8% (w/v) (r = 0.999); relative standard deviations of < 2.0% (n = 10), and sampling rate of 32 determinations per hour.

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“…This difficulty can be minimized by employing the multicommutation approach that allowed facilities to handle several reagent solutions using a single pumping channel [19,20].…”

Section: Introductionmentioning

confidence: 99%

“…The software was designed to work following the sequence depicted in the valves timing course of figure 1, i.e. the basic strategy of the binary sampling concept [19][20][21][22][23]. To begin the analytical process, the microcomputer sent through the PCL711 interface card a control signal to displace the injector-sliding bar to the sampling position (figure 4).…”

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Automatic flow system for simultaneous determination of iron and chromium in steel alloys employing photometers based on LEDs as radiation source

Fernandes

Reis

Campos

2003

Journal of Analytical Methods in Chemistry

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A multicommutated flow system for simultaneous determination of iron and chromium in steel alloys by photometry is described. The flow network consisted of an automatic injector and four solenoid valves assembled to form two independent analytical pathways, each one comprising reaction coils and a flow cell. The light source (LED) and detector (photodiode) were attached to the flow cells to form a compact unit. The flow system was microcomputer controlled by Quick BASIC 4.5 software, which carried out all steps of the analytical procedure. The feasibility of the system was proved by the determination of iron and chromium in steel alloys and its accuracy was accessed by comparing results with those obtained by plasma atomic emission spectrometry (ICP-AES). No significant difference at the 95% confidence level was observed.Other profitable features such as low reagent consumption (0.33 mg 1,10-phenantroline and 0.03 mg 1,5-diphenylcarbazide per determination); relative standard deviations (n ¼ 5) of 0.4% for iron and 1.2% for chromium; and an analytical throughput of 160 determinations per h were also achieved. IntroductionThe simultaneous determination of two or more analytes at a time by flow-injection analysis became very attractive after the work proposed by Stewart and Ruzicka (1976) [1]. Afterwards, a large number of flow procedures for multiparameter determination per sample using different detection techniques have been described [2][3][4][5][6].When a multidetermination flow system is implemented using UV-Vis spectrophotometry as the detection technique, the reagents' incompatibility is one difficulty that may appear. This drawback has been surmounted by designing flow systems based on merging zones [2,3] or on sandwich-technique approaches [4]. When analytes compound absorb radiation at the same wavelengths, the flow networks have been designed to determine each analyte at a different time [5]. On the other hand, if chemical species absorb at a different wavelength, simultaneous determination had been carried out, nevertheless equipment with the ability to sweep automatically the wavelengths have been employed [6,7].A light-emitting diode (LED) has been employed as a radiation source in some photometric procedures, its advantages being robustness and low current consumption [8,9]. Nevertheless, depending on the LED type, the width of the emission band can range from 30 to 100 nm [10][11][12][13]. However, by carefully selecting the methods, LEDs can became a good option as a radiation source in flow system when multidetermination is performed with photometric detection employing non-expensive instrumentation [14][15][16][17].The flow network for multicomponent determination can became complex, mainly when the selected spectrophotometric methods required two reagent solutions per analyte [3,18]. This difficulty can be minimized by employing the multicommutation approach that allowed facilities to handle several reagent solutions using a single pumping channel [19,20].In the present work, the intention ...

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Multicommutation in flow analysis. Part 5: Binary sampling for sequential spectrophotometric determination of ammonium and phosphate in plant digests

Cited by 31 publications

References 12 publications

Multi‐commutation in Flow Analysis: A Versatile Tool for the Development of the Automatic Analytical Procedure Focused on the Reduction of Reagent Consumption

Multi‐commutation in Flow Analysis: A Versatile Tool for the Development of the Automatic Analytical Procedure Focused on the Reduction of Reagent Consumption

Automatic Procedure Exploiting Multicommutation in Flow Analysis for Simultaneous Spectrophotometric Determination of Nonstructural Carbohydrates and Reducing Sugar in Forage Materials

Automatic flow system for simultaneous determination of iron and chromium in steel alloys employing photometers based on LEDs as radiation source

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