On-line coupling of partial-filling micellar electrokinetic chromatography with mass spectrometry

Muijselaar, Pim G.; Otsuka, Koji; Terabe, Shigeru

doi:10.1016/s0021-9673(97)01089-3

Cited by 61 publications

(62 citation statements)

References 16 publications

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“…First, the ESI process is very susceptible for nonvolatile background electrolytes (BGEs) and constituents, and this restricts the choice of BGEs amenable to CE-MS. Second, effective ESI is limited to relatively polar compounds, and may therefore not be a suitable option when neutral and/or less polar compounds are to be analyzed. In an attempt to overcome these limitations, only few studies explored the potential of alternative ionization techniques for CE-MS, such as atmospheric pressure chemical ionization (APCI) [2][3][4][5] and, more recently, atmospheric pressure photoionization (APPI) [6 -9]. Owing to its capability to form both even-and odd-electron ions, the latter technique was found suitable for ionization of both polar and apolar compounds.…”

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confidence: 99%

“…However, the caffeine concentration (1 mM) was not representative for most analytical tasks. Muijselaar et al [3] evaluated APCI as a part of a study on partial-filling MEKC-MS. For caffeine and ethenzamide concentrations of 0.5 mg/mL detectable signals were obtained. In a followup study by Isoo et al [4], initial sample concentrations (100 -1000 g/mL) were also high, but a 100-to 600-fold enhancement in sensitivity was achieved using on-line sample concentration.…”

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Capillary electrophoresis-atmospheric pressure chemical ionization-mass spectrometry using an orthogonal interface: Set-up and system parameters

Hommerson

Khan

Jong

et al. 2009

J. Am. Soc. Mass Spectrom.

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The feasibility of atmospheric pressure chemical ionization (APCI) as an alternative ionization technique for capillary electrophoresis-mass spectrometry (CE-MS) was investigated using a grounded sheath-flow CE-MS sprayer and an orthogonal APCI source. Infusion experiments indicated that highest analyte signals were achieved when the sprayer tip was in close vicinity of the vaporizer entrance. The APCI-MS set-up enabled detection of basic, neutral, and acidic compounds, whereas apolar and ionic compounds could not be detected. In the positive ion mode, analytes could be detected in the entire transfer voltage range (0 -5 kV), whereas highest signal intensities were observed when the corona discharge current was between 1000 and 2000 nA. In the negative ion mode, the transfer voltage typically was 500 V and the optimum corona discharge current was 6000 nA. Analyte signals were raised with increasing nebulizing gas pressure, but the pressure was limited to 25 psi to avoid siphoning and current drops. Signal intensities appeared to be optimal and constant over a wide range of sheath liquid flow rate (5-25 L/min) and vaporizer temperature (200 -350°C). APCI-MS signals were unaffected by the composition of the background electrolyte (BGE), even when it contained sodium phosphate and sodium dodecyl sulfate (SDS). Consequently, BGE composition, sheath-liquid flow rate, and vaporizer temperature can be optimized with respect to the CE separation without affecting the APCI-MS response. The analysis of a mixture of basic compounds and a steroid using volatile and nonvolatile BGEs further demonstrates the feasibility of CE-APCI-MS. Detection limits (S/N ϭ 3) were 1.6 -10 M injected concentrations. (J Am Soc Mass

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Capillary electrophoresis-atmospheric pressure chemical ionization-mass spectrometry using an orthogonal interface: Set-up and system parameters

Hommerson

Khan

Jong

et al. 2009

J. Am. Soc. Mass Spectrom.

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“…A corrente é interrompida antes que o eletrólito micelar alcance o detector, evitando assim a contaminação deste. 36,37 A combinação de MEKC com ESI-MS foi demonstrada com sucesso na análise de compostos quirais por Shamsi et al. 38 O polisódio N-undecanoil-L-valinato foi empregado como tensoativo por ser compatível com MS. O uso deste sistema micelar demonstrou-se vantajoso uma vez que o tensoativo polimérico auxiliou no processo de ionização, levando a uma alta relação sinal/ruído, comparada a sistemas monoméricos (Figura 2).…”

Section: Introductionunclassified

Eletroforese capilar acoplada à espectrometria de massas (CE-MS): vinte anos de desenvolvimento

Assunção¹,

Bechara²,

Simionato³

et al. 2008

Quím. Nova

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Recebido em 29/1/08; aceito em 7/5/08; publicado na web em 8/10/08 CAPILLARY ELECTROPHORESIS COUPLED TO MASS SPECTROMETRY (CE-MS): TWENTY YEARS OF DEVELOPMENT. CE-MS has been increasingly used for analysis of a vast array of compounds. This article reviews the different electrophoretic modes, interfaces and mass analyzers that are commonly used in the CE-MS coupling, as well as the technique advantages and performance characteristics. A large compilation of CE-MS applications is also presented. Therefore, this review is both a guide for beginners and a collection of key references for people who are familiar to the technique. Furthermore, this is the first CE-MS review published in a Brazilian journal and marks the installation of the first two commercial CE-MS units in Sao Paulo State.Keywords: capillary electrophoresis; electrospray ionization; mass spectrometry. introdUÇÃoA eletroforese capilar (CE) vem ocupando um espaço crescente na química analítica como uma poderosa ferramenta de separação e identificação de uma ampla gama de moléculas. A CE possui alta resolução e eficiência, parâmetros estes de grande importância em um processo de separação. Outra vantagem é o baixo custo operacional: mesmo em condições em que se empregam solventes orgânicos, os volumes consumidos de amostra e eletrólito são desprezíveis comparados à cromatografia líquida de alta eficiência (HPLC), até mesmo quando a última é utilizada em escala capilar. Ressaltamos também que os processos eletroforéticos têm como característica positiva a pequena quantidade de amostra injetada (ordem de nL), fator de importância em aplicações clínicas. Porém a maior contribuição que a CE oferece é sua complementaridade aos métodos já estabelecidos, devido à variedade de modos de separação existentes -e muitos ainda em desenvolvimento -os quais permitem a análise de praticamente todas as classes de compostos.1-3 A CE acoplada à espectrometria de massas (CE-MS) surgiu, aproximadamente, há duas décadas, e foi e vem sendo usada em diferentes aplicações, com crescente aceitação. O sucesso desta combinação alia o alto poder de resolução e eficiência da CE com a universalidade e sensibilidade que a MS oferece frente a outros sistemas de detecção como, por exemplo, espectrofotometria na região do UV-visível, bem como fluorescência induzida a laser (LIF -laser induced fluorescence), que são pouco informativos em relação à estrutura do analito. Um exemplo de tais características de MS envolve seu uso juntamente a ferramentas computacionais, o que é altamente recomendado em estudos envolvendo amostras complexas (como proteínas, peptídeos e metabólitos), já que informações como massa molecular e estrutura (MS em tandem) são indispensáveis para caracterização e quantificação de tais analitos.Desta forma, as informações oferecidas pela segunda dimensão do detector de massas constituem uma outra vantagem do uso de CE-MS. Assim, solutos que apresentam pequenas variações no tempo de migração, ou até mesmo que migram com a mesma velocidade, podem ser identificados. Nest...

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“…However, MEKC can also be combined with diode array and MS detectors, thereby yielding second-order analytical systems. The presence of micelles in the electrolyte may cause problems when hyphenating MEKC to MS, but in this case the partial filling technique can be applied, where only part of the capillary is filled with the micellecontaining solution to avoid contact between the micelles and the MS interface [4,5].…”

Section: Introductionmentioning

confidence: 99%

Micellar electrokinetic chromatography with on‐line Fourier transform infrared detection

et al. 2003

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Micellar electrokinetic chromatography (MEKC) was successfully coupled to Fourier transform infrared (FTIR) detection, using a micromachined IR-transparent flow cell with an optical path length of 15 micro m for the on-line detection of five neutral analytes. Tight connections between the flow cell and the capillaries were achieved by creating a small O-ring of UV-curing epoxy adhesive on the sharply cut capillary ends. The background electrolyte consisted of 15 mM phosphate buffer at pH 7 and 40 mM sodium dodecyl sulfate (SDS). Five analytes (paracetamol, caffeine, p-nitro benzyl alcohol, m-nitrophenol and p-nitrophenol) were successfully separated, yielding detailed IR stack plots that could be used for quantification and identification. Linear calibration graphs were obtained for each individual analyte present in mixtures at concentrations up to 10 mM. The limit of detection (3 S/N) ranged between 1.1 and 1.5 mM (1.2-1.8 ng). Analytes were identified by comparing spectra obtained during the MEKC separation with those resulting from completely filling the capillary with each individual analyte dissolved in the micelle-containing electrolyte. Information on the specific functional groups of all analytes could be elucidated from the spectra. Since FTIR is a nondestructive detection technique, a conventional on-line UV detector was introduced directly after the developed IR flow cell to test the system's performance and to demonstrate that tandem FTIR and UV detection is feasible.

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On-line coupling of partial-filling micellar electrokinetic chromatography with mass spectrometry

Cited by 61 publications

References 16 publications

Capillary electrophoresis-atmospheric pressure chemical ionization-mass spectrometry using an orthogonal interface: Set-up and system parameters

Capillary electrophoresis-atmospheric pressure chemical ionization-mass spectrometry using an orthogonal interface: Set-up and system parameters

Eletroforese capilar acoplada à espectrometria de massas (CE-MS): vinte anos de desenvolvimento

Micellar electrokinetic chromatography with on‐line Fourier transform infrared detection

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