Electrochemiluminescent Determination of l-Cysteine with a Flow-Injection Analysis System

Zhu, Lihua; Li, Yingxiu; Zhu, Guonian

doi:10.2116/analsci.19.575

Cited by 17 publications

(7 citation statements)

References 19 publications

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“…The new ECL flow cell has overcome the drawbacks of the conventional ECL flow cells as follows: First, the new ECL flow cell has a very small dead volume. The volume of the thin layer is estimated to be less than 100 nL, which is ∼1−2 orders less than those of the conventional ECL flow cells (normally varying from 1 to 30 μL). − , Therefore, the newly designed ECL flow cell will decrease the dilution of samples and thus improve the detection sensitivity for FIA; moreover, it can be used as an ECL detector for HPLC and even high-performance capillary electrophoresis (HPCE) . Second, the new ECL flow cell has a very low IR drop.…”

Section: Resultsmentioning

confidence: 99%

“…The ECL thin-layer flow cells made by different researchers might be quite different in appearance; − however, most of them were derived from the same basic design as shown in Figure . The working electrode (WE) was placed in a thin-layer solution, the counter electrode (CE) was usually a stainless steel pipe near the outlet of solution, and the reference electrode was located near the inlet (Figure A) 22 or the outlet (Figure B) of the solution. − This type of ECL flow cell had the following drawbacks: (1) large dead volume, especially when the reference electrode was placed near the inlet (Figure A), would reduce both the detection sensitivity and separation efficiency of sample in HPLC; (2) high IR drop, especially when the reference electrode was located at the downstream (Figure B), caused high overpotential and thus decreased the sensitivity of ECL detection; (3) high flow resistance made it difficult to remove away possible gas bubbles, which would cause significant noise . To overcome the above drawbacks, a new type of ECL flow cell with small dead volume, IR drop, and flow resistance was designed and used in our homemade FIA-ECL system.…”

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confidence: 99%

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Flow Injection Analysis System Equipped with a Newly Designed Electrochemiluminescent Detector and Its Application for Detection of 2-Thiouracil

et al. 2006

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A new flow injection analysis (FIA) system equipped with an electrochemiluminescent (ECL) detector has been developed and applied for the ECL detection of 2-thiouracil. The FIA-ECL system used a specially designed flow-through ECL thin-layer cell to reduce the dead volume, the IR drop across the cell, and the probability of accumulation of gas bubbles in the cell. It was thus envisioned to improve the detection limit of the FIA-ECL method. After being established, the new FIA-ECL system was used to investigate the ECL response of 2-thiouracil in the presence of the ECL of Ru(bpy)3(2+). It was found that 2-thiouracil could enhance the ECL of Ru(bpy)3(2+) over a wide pH range (pH 4.0-12.0). A highly sensitive method for detection of 2-thiouracil in biological samples was developed by the new FIA-ECL system after optimizing several experimental conditions, such as the applied potential of the working electrode, the pH value of the aqueous solution, the flow rate of carrier solution, and the concentration of Ru(bpy)3(2+).

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

Flow Injection Analysis System Equipped with a Newly Designed Electrochemiluminescent Detector and Its Application for Detection of 2-Thiouracil

et al. 2006

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“…The detection limit obtained for Cys in the present study was compared with the reported papers and are given in Table S1. It can be seen from Table S1, the lowest detection limit was achieved in the present study for Cys by any other methods [9,14,16,[35][36][37][38][39][40][41].…”

Section: Spectrofluorimetric Determination Of Cysmentioning

confidence: 61%

4-Amino-6-hydroxy-2-mercaptopyrimidine capped gold nanoparticles as fluorophore for the ultrasensitive and selective determination of l-cysteine

Shankar

John

2015

Sensors and Actuators B: Chemical

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“…Thereby, cysteine and cystine are widely used in many pharmaceutical products and as supplement in some foods. [1][2][3] As cysteine is readily oxidized to cystine in air, and cystine is hydrolyzed to cysteine in water, they are often presented together (in hair, liver, horn, etc.). So, the determination of cysteine and cystine in biological fluids, clinical investigations and pharmaceutical preparations are of great importance.…”

Section: Introductionmentioning

confidence: 99%

Flow injection spectrofluorimetric determination of cystine and cysteine

Ensafi

Rezaei

Nouroozi³

2009

J. Braz. Chem. Soc.

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Um procedimento relativamente simples e sensível com detecção espectrofluorimétrica foi desenvolvido para a determinação de cistina e cisteína por sistema de injeção em fluxo com determinação seqüencial. Esse método é fundamentado na redução de Tl(III) com cisteína em meio ácido, produzindo o reagente fluorescente TlCl 3 2-(λ ex = 227 nm, λ em = 419 nm). Antes da injeção, a solução da amostra foi dividida em dois fluxos. O primeiro fluxo foi tratado com coluna de redução de Cd e então refluxado com a solução do carregador para reagir em pH 5,0 com Tl(III), passado através de uma cela de reação de 100 cm e posteriormente para a cela fluxo do espectrofluorímetro, onde a intensidade de fluorescência foi medida (λ ex = 227 nm, λ em = 419 nm). Esse sinal está relacionado às concentrações de cistina e cisteína. O segundo fluxo da solução de amostra foi injetado diretamente no fluxo carregador para reagir e, então, pela cela de reação e detector para medida da intensidade de fluorescência. O sinal nessa etapa é relacionado apenas à cisteína. Assim, o conteúdo de cistina foi determinado diretamente da diferença entre os dois sinais. Cistina e cisteína podem ser determinadas no intervalo de 0,10 a 5,50 μmol L -1 e 0,20 a 8,0 μmol L -1 , respectivamente, em uma razão de 20 amostras por hora. O limite de detecção (3s/k) foi 0,10 μmol L -1 para os dois analitos. Os desvios padrões relativos para a determinação de dez replicatas de 4,0 e 3,5 μmol L -1 de cistina ou cisteína foram 1,1% e 1,8%, respectivamente. A influência de substâncias interferentes foi estudada. O método proposto foi aplicado com sucesso na determinação seqüencial de ambos analitos em amostras farmacêuticas.A relatively simple and sensitive procedure with spectrofluorimetric detection was developed for the determination of cystine and cysteine by flow injection system with sequential determination. This method is based on the reduction of Tl(III) with cysteine in acidic media, producing a fluorescence reagent, TlCl 3 2-(λ ex = 227 nm, λ em = 419 nm). Before injection, the sample solution was divided into two streams. The first stream was treated with Cd reduction column and then joined with the carrier to react with Tl(III) at pH 5.0 and then passed through a 100 cm reaction coil to the flow cell of the spectrofluorimeter, where the fluorescence intensity was measured (λ ex = 227 nm, λ em = 419 nm). This signal is related to cystine and cysteine concentrations. The second stream of sample solution was injected directly into the carrier stream to react with the reagents and then passed through the reaction coil and detector for measuring the fluorescence intensity. The signal in this step is related only to cysteine. Thus, the cystine content was determined directly from difference of the two signals. Cystine and cysteine can be determined in the range of 0.10 to 5.50 μmol L -1 and 0.20 to 8.0 μmol L -1, respectively, at a rate of 20 samples per hour. The limit of detection (3s/k) was 0.10 μmol L -1 for both analytes. The relative standard deviations for te...

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Electrochemiluminescent Determination of l-Cysteine with a Flow-Injection Analysis System

Cited by 17 publications

References 19 publications

Flow Injection Analysis System Equipped with a Newly Designed Electrochemiluminescent Detector and Its Application for Detection of 2-Thiouracil

Flow Injection Analysis System Equipped with a Newly Designed Electrochemiluminescent Detector and Its Application for Detection of 2-Thiouracil

4-Amino-6-hydroxy-2-mercaptopyrimidine capped gold nanoparticles as fluorophore for the ultrasensitive and selective determination of l-cysteine

Flow injection spectrofluorimetric determination of cystine and cysteine

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