Electrophoretic separations with polyether ether ketone capillaries and capacitively coupled contactless conductivity detection

Tanyanyiwa, Jatisai; Leuthardt, Sandro; Hauser, Peter C.

doi:10.1016/s0021-9673(02)01425-5

Cited by 55 publications

(48 citation statements)

References 19 publications

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“…Tanyanyiwa et al [41] showed that the use of a CCD is also possible in polyether ether ketone (PEEK) capillaries, which are not transparent and therefore cannot be employed with optical detection. This tubing material allows the rapid switching between the determination of cations and anions without changing the buffer solution as usually required when using the standard fused silica capillaries.…”

Section: Instrumental Developmentsmentioning

confidence: 99%

“…Thanks to its good separation efficiency, low specific conductivity but considerably high ionic strength, a buffer based on 2-(N-morpholino)ethanesulfonic acid and histidine (MES/His) has been widely used for the determination of alkali and alkaline earth cations and ammonium ions [19,20,27,32,33,36,38,40,41,47,48]. An example of such a separation is given in Figure 5.…”

Section: Inorganic Ionsmentioning

confidence: 99%

“…Cr(III) as Cr 3þ and Cr(VI) as chromate were injected from opposite ends of the separation capillary, separated together with other cations and anions and detected in the middle of the capillary. The simultaneous separation of anions and cations with dual opposite-end injection was also demonstrated in PEEK capillaries [41]. A detailed study on the effect of the position of the detector along the capillary was carried out by Macka et al [39].…”

Section: Simultaneous Determination Of Anions and Cationsmentioning

confidence: 99%

See 2 more Smart Citations

Contactless Conductivity Detection in Capillary Electrophoresis: A Review

2004

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The popularity of contactless conductivity detection in capillary electrophoresis has been growing steadily over the last few years. Improvements have been made in the design of the detector in order to facilitate its handling, to allow easy incorporation into available instruments or to achieve higher sensitivity. The understanding of its fundamental working principles has been advanced and the detection approach has also been transferred to lab-on-chip devices. The range of applications has been extended greatly from the initial work on small inorganic ions to include organic species and biomolecules. Concurrent determination of cations and anions by dual injection from opposite ends has been demonstrated as well as sample introduction by using flow-injection systems for easy automation of the process.

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Section: Instrumental Developmentsmentioning

confidence: 99%

Section: Inorganic Ionsmentioning

confidence: 99%

Section: Simultaneous Determination Of Anions and Cationsmentioning

confidence: 99%

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Contactless Conductivity Detection in Capillary Electrophoresis: A Review

2004

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“…However, the chemical stability of currently available coated capillaries is limited, and the accessible pH range is comprised between 2 and 10 [12,13]. Plastics have become important materials for manufacturing microfluidic devices for electrodriven separations [14,15], but only a few CE experiments have been reported in the last 10 year using polymeric capillary columns [16][17][18][19][20][21][22][23][24][25][26][27]. This is mainly due to their inferior optical, mechanical, and thermal properties, and also because of the great versatility of fused-silica capillary columns.…”

Section: Introductionmentioning

confidence: 99%

CE‐ESI‐MS of biological anions in plastic capillaries at high pH

et al. 2007

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In this study, the potential of poly(methylmethacrylate) (PMMA, Plexiglas) and polyether ether ketone (PEEK) tubing for CE-ESI-MS separations of anions at high pH values was examined. A set of model compounds of biological interest was used to investigate the main operational parameters for CE-ESI-MS, such as the sheath-flow interface design, the polarity of the ionization voltage, the use of ammonia-based separation electrolytes, and the sheath liquid composition. Optimum separations and detection sensitivities in negative ESI mode were obtained using a running electrolyte of 75 mM of ammonia at pH 11 and a sheath liquid of 60:40 v/v or 75:25 v/v isopropanol/water with 0.5% v/v of ammonia. At these experimental conditions, PMMA and PEEK capillaries show good hydrolytic stabilities and lower EOF values than fused-silica columns. Better separation resolutions were obtained with PMMA capillary, but this plastic rapidly swelled and bled because of its limited chemical resistance to the sheath liquid. PMMA columns equipped with a fused-silica tip were used for a safer exposure to the sheath liquid, but the inner surface of the fused-silica tips had limited stability at pH 11. On the other hand, good separations and reproducibility on migration times and peak areas were obtained using PEEK capillaries without capillary column deterioration.

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“…Um detector oscilométrico desenvolvido por Fracassi da Silva e Lago 23 opera com freqüência de 600 kHz e 20 V pico-a-pico entre dois eletrodos cilíndricos distantes 1 mm entre si, os quais são construídos pintando-se duas faixas com tinta à base de prata sobre a superfície de um capilar, perpendicularmente ao seu eixo. Por sua versatilidade, o campo de aplicação da detecção oscilométrica em eletroforese capilar tem crescido intensivamente 21,[24][25][26][27][28][29] . A simplicidade do equipamento de eletroforese e o baixo custo dos componentes, relativamente a outros equipamentos analíticos, tornam possível sua construção em laboratório, com a vantagem sobre os equipamentos comerciais de permitir modificações e adaptações.…”

Section: Introductionunclassified

Um equipamento de eletroforese capilar com detecção condutométrica construído em laboratório

et al. 2005

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Recebido em 11/8/04; aceito em 30/3/05; publicado na web em 24/8/05A LABORATORY-MADE CAPILLARY ELECTROPHORESIS EQUIPMENT WITH CONDUCTOMETRIC DETECTION. A new construction of a capillary electrophoresis instrument with a universal conductivity detector (oscillometric detector) is described. The performance of the electrophoresis equipment was evaluated through the separation and detection of inorganic anions and cations in aqueous solutions. The results reproduced those found in the literature for the investigated probe ions, showing an efficient separation and good repeatability.Keywords: capillary electrophoresis instrument; oscillometric detector; inorganic ions. INTRODUÇÃOA importância da eletroforese capilar (CE) na análise de misturas complexas decorre da alta eficiência de separação e da simplicidade do equipamento utilizado 1 . O processo de separação dos componentes da mistura, injetada em um eletrólito de corrida que flui através do capilar, consiste no deslocamento do soluto sob a ação de um campo elétrico. As partículas ou íons migram na direção do cátodo ou do ânodo em função de sua carga específica 2 e a separação decorre das diferenças de mobilidade dos compostos iônicos ou ionizáveis presentes, da razão carga/volume das espéci-es e de fatores estruturais 3,4 . O eletroferograma, isto é, o registro gráfico do sinal do detector em função do tempo decorrido a partir da injeção da amostra, permite identificar e quantificar os componentes da mistura.A análise por eletroforese tem sua origem no método da fronteira móvel 5,6 . Posteriormente, para evitar o processo de convecção devido à força gravitacional, o tubo de vidro foi substituído por uma tira de papel ou empacotado com um meio quimicamente estável como pó de vidro, celulose ou gel 7 . Por sua vez, o efeito de convecção causado pela geração de calor devido à passagem de corrente elétrica através da solução foi minimizado por Hjertén pela rotação de um capilar com 3 mm de diâmetro interno (d.i. A escolha do método de detecção na eletroforese capilar depende, entre outros fatores, da compatibilidade do detector com as dimensões do capilar. Tradicionalmente, tem sido empregada a espectrometria de absorção molecular no UV-visível e, mais recentemente, a espectrometria de massas 1,11 . Por outro lado, as téc-nicas de detecção eletroquímica são especialmente adequadas à determinação de analitos que não são detectáveis por métodos ópticos 1,12-14 e quando são empregados tampões biológicos, que absorvem fortemente na região do ultra-violeta 15 . Para minimizar a interferência do elevado campo elétrico empregado na separação dos analitos no potencial do eletrodo de trabalho, emprega-se um desacoplador. Este consiste basicamente de uma fissura feita pró-xima da extremidade do capilar e coberta com um material poroso 1 . Este tipo de detecção apresenta como inconvenientes 13,14,16,17 a geração de gás no eletrólito de corrida, o maior tempo necessário para limpeza do eletrodo, seu alinhamento em relação à extremidade do capilar e sua calibração. O método ele...

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Electrophoretic separations with polyether ether ketone capillaries and capacitively coupled contactless conductivity detection

Cited by 55 publications

References 19 publications

Contactless Conductivity Detection in Capillary Electrophoresis: A Review

Contactless Conductivity Detection in Capillary Electrophoresis: A Review

CE‐ESI‐MS of biological anions in plastic capillaries at high pH

Um equipamento de eletroforese capilar com detecção condutométrica construído em laboratório

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