Multi-site detection in flow analysis

Zagatto, Elias A.G.; Fo, H. Bergamin; Brienza, Sandra Maria Boscolo; Arruda, Marco Aurélio Zezzi; Nogueira, Ana Rita A.; Lima, José L.F.C.

doi:10.1016/0003-2670(92)80176-8

Cited by 36 publications

(18 citation statements)

References 21 publications

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“…1), a Gilson Minipuls 3 peristaltic pump pumped solutions and the intercalation of sample and standards segments was made through an injector-commutator of circular movement [18], with functioning characteristics similar to that with horizontal movement previously referred to in the literature [19]. Connection between the different system components was made through Teflon tubing (Omnifit) of 0.8 mm internal diameter.…”

Section: Apparatusmentioning

confidence: 99%

Automatic Determination of Uric Acid in Urine in a FIA System with a Tubular Amperometric Detector

Garcia

Lima

Silva

et al. 2004

Port. Electrochim. Acta

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This paper describes the use of a FIA system for the automatic determination of uric acid in urine, using a tubular amperometric detector. In this system, glassy carbon electrodes of tubular configuration were activated by successive cyclical scans from -0.30 to 2.00 V versus Ag/AgCl reference electrode in 0.50 mol.L -1 sulphuric acid solution. Samples were diluted in supporting electrolyte before analysis and no other pre-treatment was employed. Such dilution enabled the matrix effects to be reduced and therefore improving the sensitivity provided by the activation step that allows the uric acid (UA) to be detected at lower concentration levels after dilution. Uric acid determination was performed in a single channel FIA manifold, which provided reproducibility of sample transport to the detector and enabled a sampling rate of 120 samples per hour to be achieved. The tubular configuration of the cell offered robustness to the system since it was rigidly fixed to the manifold, allowing the manifold to be generalised for routine analysis application. The results obtained with the FIA system for UA determination in urine were compared with those from the enzymatic method used in clinical analysis laboratories. No statistical difference between methods was found at the 95% confidence level. Relative deviations between both methods were within ± 4% and the proposed system showed good repeatability (about 3%, n = 10).

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Section: Apparatusmentioning

confidence: 99%

Automatic Determination of Uric Acid in Urine in a FIA System with a Tubular Amperometric Detector

Garcia

Lima

Silva

et al. 2004

Port. Electrochim. Acta

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“…The equipment set-up consisted of two LEDs-based photometers constructed to implement the work; an IPC8 Ismatec peristaltic pump furnished with Tygon tubes; a home-made automatic commutator injector with two commutation sections, which was controlled by means of two solenoids attached to its sliding bar [21]; four 161T031 three-way solenoid valves (NResearch, Stow, MA, USA); a 486 microcomputer equipped with a PCL711S interface card (American Advantech, San Jose, CA, USA); and a home-made electronic interface to match voltage and current intensities required to switch on the commutator injector and solenoid valves [18]. Reaction coils and flow lines were of polyethylene tubing (i.d.…”

Section: Apparatusmentioning

confidence: 99%

“…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].…”

Section: Introductionmentioning

confidence: 99%

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

Fernandes¹,

Reis²,

Campos³

2003

Journal of Automated Methods & Management in Chemistry

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“…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].…”

mentioning

confidence: 99%

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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Multi-site detection in flow analysis

Cited by 36 publications

References 21 publications

Automatic Determination of Uric Acid in Urine in a FIA System with a Tubular Amperometric Detector

Automatic Determination of Uric Acid in Urine in a FIA System with a Tubular Amperometric Detector

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

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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