Use of an Ion Trap Storage/Reflectron Time-of-Flight Mass Spectrometer as a Rapid and Sensitive Detector for Capillary Electrophoresis in Protein Digest Analysis

Wu, Jing; Qian, Mark G.; Li, Michael X.; Liu, Lin; Lubman, David M.

doi:10.1021/ac960405v

Cited by 75 publications

(54 citation statements)

References 33 publications

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“…When using non-conductive glass or fused-silica capillaries, the voltage at the spray tip is applied in two different ways, either by liquid contact with an electrode at some point before the needle tip49,55,74a or by coating of the capillary with gold23,29,74b or silver. 75 In tips employing a liquid contact, the voltage is conducted through the mobile phase to the ESI tip. For example, as shown in Fig.…”

Section: Capillary Columnsmentioning

confidence: 99%

Comparison of conventional, narrow-bore and capillary liquid chromatography/mass spectrometry for electrospray ionization mass spectrometry: practical considerations

1999

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Section: Capillary Columnsmentioning

confidence: 99%

Comparison of conventional, narrow-bore and capillary liquid chromatography/mass spectrometry for electrospray ionization mass spectrometry: practical considerations

1999

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“…8,9,22,23 One of the most commonly used techniques for protein identification by mass spectrometry is peptide mapping in conjunction with a protein database search. In order to identify a protein using a protein database, several pieces of information are needed, including the average molecular weight (MW) of the protein and the masses of several peptide fragments obtained through the enzymatic digestion of the protein of interest.…”

mentioning

confidence: 99%

Capillary electrophoresis/electrospray ionization high mass accuracy time-of-flight mass spectrometry for protein identification using peptide mapping

Cao

Moini

1998

Rapid Commun. Mass Spectrom.

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Capillary electrophoresis/electrospray ionization (CE/ESI) high mass accuracy time-of-flight mass spectrometry was used for the first time to characterize small proteins using peptide mapping. To identify small proteins, the intact proteins were first analyzed to obtain their average molecular weights with errors less than 1 Da. On-line capillary electrophoresis mass spectrometry of the tryptic digests of these small proteins was then performed to obtain the accurate molecular weights of the peptides with accuracies of approximately 10 ppm. Next, this information was used for the identification of the proteins using a protein database. It was found that high mass accuracy is an effective tool in reducing the list of most-likely proteins generated by the database. In addition, on-line collision-induced dissociation of the completely or partially resolved capillary electrophoresis peaks of the protein digests was used to unambiguously identify the sequences of these peptides. Each CE/ESI-MS analysis used only 5 nL of sample containing approximately 120 fmol of each peptide in protein digests. The results indicate that the combination of capillary electrophoresis and high resolution, high mass accuracy time-of-flight mass spectrometry is a viable option for the identification of small proteins using peptide mapping.

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“…Since that time a number of reports have described fused silica capillaries coated with gold developed for use in CE/ESI-MS. [10][11][12][13] Often the tips of the emitters are sharpened to increase the electric field strength where the solution comes in contact with the metal.…”

Section: 3mentioning

confidence: 99%

Metallized sheathless electrospray emitters for use in capillary electrophoresis orthogonal time-of-flight mass spectrometry

Barnidge

Nilsson

Markides

et al. 1999

Rapid Commun. Mass Spectrom.

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Chromium-gold coated fused silica emitters for electrospray ionization have been fabricated with lifetimes upwards of 100 hours. The coating on these emitters is extremely durable withstanding electrical discharges, abrasion and mechanical stress. Usable flow rates range from 30 nL/min to 1 mL/min using both standard electrospray solutions and aqueous buffers. Coated capillary electrophoresis columns incorporating the emitter provide excellent separation, low limits of detection (70-700 attomoles for peptides), and are easy to use. Performance of the emitters in continuous infusion experiments and capillary electrophoresis/ electrospray ionization mass spectrometry applications are presented. Copyright # 1999 John Wiley & Sons, Ltd. Received 27 February 1999; Revised 30 March 1999; Accepted 31 March 1999 Fused silica capillaries have played an important role in the development of electrospray ionization mass spectrometry (ESI-MS) since they provide a durable, non-reactive, and inexpensive way to couple various flow streams to ESI sources. Although fused silica capillaries are ideally suited for transporting solutions to an ESI source, they cannot be used to provide an electrical connection at the ESI source without modification since fused silica is a nonconductive material. Despite this fact, a variety of distinct approaches have been taken to try and get around the problem of applying a high potential to a solution flowing in a nonconductive fused silica capillary in order to generate an electrospray. Niessen 1 presents a good review of this topic in relation to atmospheric pressure ionization (API) sources in a recent article.One solution to this problem is to coat the fused silica capillary with a conductive metal. Metallized fused silica capillaries have been used extensively as emitters for ESI, with silver and gold being the most commonly used metals for coating. Silver can be deposited onto a fused silica ESI tip using a variety of means ranging from liquid silver solder to vapor deposition. However, the silver layer is unstable under the red-ox conditions at the ESI tip, resulting in the degradation of the electrical contact between the silver and the capillary electrophoresis (CE) buffer. Gold on the other hand is most often sputtered onto a fused silica ESI tip, but it can also be electroplated. Although gold is more electrochemically stable than silver, it is physically unstable on fused silica and has a finite lifetime before electrical contact is lost and the gold must be reapplied. Nonetheless, coating capillaries with a conductive metal continues to be a viable alternative for creating an electrical contact since this type of design (a.k.a. sheathless design) allows for low flow rates to be used. This is of particular importance when coupling capillary electrophoresis to electrospray ionization mass spectrometry (CE/ESI-MS) since flow rates are dictated by the electroosmotic flow (EOF) that is generated, which can range from 10-200 nl/min depending on the CE conditions used. ESI emitters workin...

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Use of an Ion Trap Storage/Reflectron Time-of-Flight Mass Spectrometer as a Rapid and Sensitive Detector for Capillary Electrophoresis in Protein Digest Analysis

Cited by 75 publications

References 33 publications

Comparison of conventional, narrow-bore and capillary liquid chromatography/mass spectrometry for electrospray ionization mass spectrometry: practical considerations

Comparison of conventional, narrow-bore and capillary liquid chromatography/mass spectrometry for electrospray ionization mass spectrometry: practical considerations

Capillary electrophoresis/electrospray ionization high mass accuracy time-of-flight mass spectrometry for protein identification using peptide mapping

Metallized sheathless electrospray emitters for use in capillary electrophoresis orthogonal time-of-flight mass spectrometry

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