Liquid junction coupling for capillary zone electrophoresis/ion spray mass spectrometry

Lee, Edgar D.; Mück, Wolfgang; Henion, Jack D.; Covey, Thomas R.

doi:10.1002/bms.1200180932

Cited by 205 publications

(115 citation statements)

References 23 publications

Supporting

Mentioning

115

Contrasting

Order By: Relevance

“…ESI has become one of the most important and powerful ionization techniques for MS because of its effectiveness in detecting large biomolecules 4 and ease-ofuse for interfacing liquid-based separation techniques such as liquid chromatography (LC) 5,6 and capillary electrophoresis (CE). [7][8][9] A conventional ESI source typically employs flow rates in the range of 4-200 μL/min through a capillary that has 50-200 μm inner diameter (i.d.). 5 A micro-electrospray source makes use of a tapered emitter with a small terminal orifice (usually < 20 μm i.d.)…”

Section: Introductionmentioning

confidence: 99%

Characterizing Electrospray Ionization Using Atmospheric Pressure Ion Mobility Spectrometry

2006

View full text Add to dashboard Cite

Reduced flow-rate electrospray ionization has been proven to provide improved sensitivity, less background noise, and improved limits of detections for ESI-MS analysis. Miniaturizing the ESI source from conventional electrospray to micro-electrospray and further down to nanoelectrospray has resulted in higher and higher sensitivity. However, when effects of flow rate were investigated for atmospheric pressure ESI-IMS using a nanospray emitter, a striking opposite result was observed. The general tendency we observed in ESI-IMS was that higher flow rate offered higher ion signal intensity throughout a variety of conditions investigated. Thus further efforts were undertaken to rationalize these contradictory results. It is well accepted that decreased flow rate increases both ionization efficiency and transmission efficiency thus improves ion signal in ESI-MS. However, our study revealed that decreased flow rate results in decreased ion signal because ion transfer is constant no matter how flow rate changes in ESI-IMS. Since ion transfer is constant in atmospheric pressure ESI-IMS, ionization efficiency can be studied independently, which otherwise is not possible in ESI-MS where both ionization efficiency and transmission efficiency vary as conditions alter. In this report, we present a systematic study on signal intensity and ionization efficiency at various experimental conditions using ESI-IMS and demonstrated the ionization efficiency as a function of flow rate, analyte concentration, and solvent composition.

show abstract

Section: Introductionmentioning

confidence: 99%

Characterizing Electrospray Ionization Using Atmospheric Pressure Ion Mobility Spectrometry

2006

View full text Add to dashboard Cite

show abstract

“…In the so-called sheathless design, the electrical contact is provided by means of an electrically conducting coated capillary tip [13]. Similarly, the electrical contact for the CE and ESI potential can be secured by applying a liquid junction between the CE capillary and an interface spray tip [14], however, bearing the risk of peak broadening at the T-junction. In both latter cases a constant flow is often achieved by the use of a coated capillary to produce a high and pH-independent EOF.…”

Section: Esimentioning

confidence: 99%

Quantitation in capillary electrophoresis-mass spectrometry

2005

View full text Add to dashboard Cite

Quantitation in capillary electrophoresis-mass spectrometryCE-MS has evolved into a strong alternative to LC-MS. Most of CE-MS applications deal with characterization and identification. However, quantitative aspects have gained importance in, e.g., pharmaceutical and biotechnological applications. Here we summarize and evaluate various methodological aspects in order to achieve sensitive and reproducible results. Similar to LC-MS, aspects of matrix influence on the electrospray process need to be carefully addressed when quantitative results are intended by CE-MS. Due to a more complicated coupling special emphasis needs to be put on the CE-MS interface. Generally linearity over more than three orders of magnitude can be achieved by CE-ESI-MS. Furthermore, a literature survey has been performed in order to give an overview over quantitative measurements performed by CE-MS. The precision can be doubled when changing from a structural related to an isotopically labeled internal standard. Thus a level of precision better than 5% RSD can be achieved.

show abstract

“…by Lee et al [6] and since then, several groups of pesticides have been determined by this technique [2,3,[7][8][9]. Nowadays, among the different interfaces developed to couple CE with MS, electrospray ionization (ESI) [10] is the most frequently used.…”

Section: Introductionmentioning

confidence: 99%

Analysis of pesticides in soy milk combining solid‐phase extraction and capillary electrophoresis‐mass spectrometry

Hernández-Borges

Rodríguez‐Delgado

García-Montelongo

et al. 2005

J of Separation Science

View full text Add to dashboard Cite

In this work, the determination of a group of triazolopyrimidine sulfoanilide herbicides (cloransulam-methyl, metosulam, flumetsulam, florasulam and diclosulam) in soy milk by capillary electrophoresis-mass spectrometry (CE-MS) is presented. The main electrospray interface (ESI) parameters (nebulizer pressure, dry gas flow rate, dry gas temperature and composition of the sheath liquid) are optimized using a central composite design. To increase the sensitivity of the CE-MS method, an off-line sample preconcentration procedure based on solid-phase extraction (SPE) is combined with an on-line stacking procedure (i.e. normal stacking mode, NSM). Samples could be injected up to 100 seconds, providing limits of detection (LODs) down to 74 μg/L, i.e., in the low ppb level, with relative standard deviation values (RSD, %) between 3.8% and 6.4% for peak areas for the same day, and between 6.5% and 8.1% for three different days. The usefulness of the optimized SPE-NSM-CE-MS procedure is demonstrated through the sensitive quantification of the selected pesticides in soy milk samples.

show abstract

Liquid junction coupling for capillary zone electrophoresis/ion spray mass spectrometry

Cited by 205 publications

References 23 publications

Characterizing Electrospray Ionization Using Atmospheric Pressure Ion Mobility Spectrometry

Characterizing Electrospray Ionization Using Atmospheric Pressure Ion Mobility Spectrometry

Quantitation in capillary electrophoresis-mass spectrometry

Analysis of pesticides in soy milk combining solid‐phase extraction and capillary electrophoresis‐mass spectrometry

Contact Info

Product

Resources

About