Water cluster calibration reduces mass error in electrospray ionization mass spectrometry of proteins

Ledman, David W.; Fox, Robert O.

doi:10.1016/s1044-0305(97)00157-8

Cited by 25 publications

(23 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is not clear whether these clusters result from incomplete desolvation in the spray plume, or from condensation during the first expansion. This result is in stark contrast to the spectrum reported by Ledman and Fox [96]. These authors used a high solvent flow rate, low drying gas flow rate, low source temperature, and omitted any counter-flow gas to promote water cluster ion formation.…”

contrasting

confidence: 60%

“…However, the measured count rate cannot be equated directly to ion flux entering the chamber, as the detection efficiency of the channeltron is significantly less than unity. Not all the ions striking the input result in a pulse that can be counted, and it cannot be guaranteed that all shown that only singly charged cluster ions are produced [96]. approximately reflects the gas flow into the analysis chamber.…”

Section: Ion Transfer Into Vacuummentioning

confidence: 99%

See 1 more Smart Citation

MEMS-Based Nanospray-Ionization Mass Spectrometer

Wright¹,

Syms

Moseley³

et al. 2010

J. Microelectromech. Syst.

View full text Add to dashboard Cite

An electrospray ionisation mass spectrometer (ESI-MS) whose main components are all fabricated using silicon microelectromechanical systems (MEMS) techniques is demonstrated for the first time. The ion source consists of a microengineered alignment bench containing a V-groove mounting for a nanospray capillary, an ion extraction electrode, and a pneumatic nebuliser. The vacuum interface consists of two plates, each carrying a 50 µm diameter capillary, that are selectively etched and bonded together to provide a differentially pumped internal cavity. The quadrupole filter consists of a microfabricated frame that provides mountings for stainless steel rods measuring 650 µm in diameter and 30 mm in length. Two different quadrupoles are compared: a firstgeneration bonded silicon device, and a second-generation silicon-on-glass device with a Brubaker prefilter. Differential pumping of a MEMS component is demonstrated for the first time, atmospheric pressure ionisation and ion transfer into vacuum are characterised, ESI-MS operation is demonstrated and spectra are presented for a variety of compounds. KEYWORDS:Mass spectrometry, Electrospray, Quadrupole filter, MEMS IntroductionOver 25 years have passed since an electrospray ionisation (ESI) source was first coupled to a quadrupole mass spectrometer (MS) by Yamashita and Fenn [1]. Since then, ESI-MS has become a workhorse of analytical chemistry, allowing analytes to be ionised at atmospheric pressure with little fragmentation and passed into a vacuum system for analysis.Conventional ESI sources employ spray tips with an internal diameter (ID) of ≈100 µm[2]. In order to establish a Taylor cone and maintain stable emission of charged droplets, minimum flow rates of 0.5 -5 µL min -1 and voltages of 2.5 -4 kV are used. However, it has been convincingly demonstrated that high sensitivity and stable emission can be achieved at much lower flow rates and voltages using spray tips with IDs of ≈ 5 µm, and silica nanospray capillaries with a range of coatings have become widely available [3][4][5][6][7][8].Unfortunately, while these are inexpensive, operator expertise and costly positioning apparatus are often required for stable and reproducible performance.Electrosprayed ions are passed into a low-pressure chamber via a vacuum interface. The simplest interface is a single orifice or capillary that allows gas and entrained ions to pass directly into the vacuum chamber. Clearly, the orifice must be small enough or the pumps large enough to ensure that the pressure is consistent with mass analysis. However, the susceptibility of very small orifices to clogging and the inconvenience of large pumps led to this approach being abandoned. Modern instruments employ one or more stages of 4 differential pumping. Larger orifices can be tolerated since only a fraction of the flow is transmitted to the vacuum chamber, while the majority of the gas load can be pumped away at higher pressure using more modest pumps.The effective transfer of ions and molecules from atmospheric pressu...

show abstract

contrasting

confidence: 60%

Section: Ion Transfer Into Vacuummentioning

confidence: 99%

MEMS-Based Nanospray-Ionization Mass Spectrometer

Wright¹,

Syms

Moseley³

et al. 2010

J. Microelectromech. Syst.

View full text Add to dashboard Cite

show abstract

“…These conditions provide ready access to a variety of nanodroplet solvated ions, such as H 3 O + , Ln 3 + , various substituted anilines, Cu 2 + , and Mg 2 + . [32][33][34][35] A pick-up technique has also proven reliable for generating many types of multiply charged solvent clusters. [36,37] In a similar manner to our previous work, in which we sequentially removed water molecules from triply charged lanthanide-centered water clusters, [35] we subjected the methylated guanidinium nanodroplets obtained to EDESI-MS/MS to observe the sequential dehydration of the charged solutes directly, under controlled conditions.…”

Section: Resultsmentioning

confidence: 99%

Insights into the Post‐Translational Methylation of Arginine from Studies of Guanidinium–Water Nanodroplets

McQuinn

McIndoe

Hof

2008

Chemistry A European J

View full text Add to dashboard Cite

Highly solvated methylated guanidinium ions ([Me nGuan(H2O)m](+); n=0-4 and 6; m=1->50), which model the various post-translationally methylated states of arginine, were generated in the electrospray ionization (ESI) source of an unmodified commercial tandem mass spectrometer. The dehydration processes of highly solvated [Me nGuan(H2O)21](+) ions were monitored by using energy-dependent ESI MS. These data, together with supporting calculations, provide a detailed picture of the interplay of methylation and hydration, and both the calculations and the experimental evidence suggest a specific structural basis for the observed effects. The ramifications for biochemical binding events that are controlled by the post-translational methylation of arginine to give dimethylarginines are discussed.

show abstract

“…This, however, resulted in small systematic mass error in the higher mass region which was corrected by recalibrating the instrument and all the acquired data. The new calibration was done with the aid of water clusters [35]. Three types of calibrations were performed on each quadrupole: a static scan calibration (50-1,800 Da), a scanning calibration (50-1,800 Da), and a scan speed compensation calibration (200-5,000 amu/s).…”

Section: Hplc-elsd-esi-ms Analysismentioning

confidence: 99%

Liquid Chromatography–Light Scattering Detector–Mass Spectrometric Analysis of Digested Oxidized Rapeseed Oil

Tarvainen

Suomela

Kuksis

et al. 2010

Lipids

View full text Add to dashboard Cite

Rapeseed oil was oxidized chemically and thermally to produce two distinct oxidized oils. These oils, along with unoxidized oils, were subjected to an artificial digestion model to simulate the digestive processes in humans. Lipid digestion involves lipases that break down the intact triacylglycerol (TAG) molecules first to diacylglycerols, and eventually to sn-2-monoacylglycerols (MAG) and free fatty acids. A high performance liquid chromatography-evaporative light scattering detector-electrospray ionization-mass spectrometric (HPLC-ELSD-ESI-MS) method was developed to monitor the lipolysis and the presence of oxidized lipids. The HPLC-ELSD-ESI-MS analysis enabled the separation and detection of nearly all the lipid species present in the sample after TAG hydrolysis. The HPLC-MS analyses of digestion products revealed that oxidized triacylglycerols are hydrolyzed by the digestive enzymes in a manner similar to that of native, unoxidized molecules. Significant amounts of sn-1(3)-MAG were found in all the samples after lipolysis, however, more of these were found in unoxidized rapeseed oil samples than in the oxidized oils. Several oxidized molecules were identified with the aid of synthesized oxylipids. This novel method is scalable to small-scale preparative fractionation of oxidized lipid molecules from a complex digestion sample. Also, the fingerprint-like, diagnostic, MS profiles of oxidized oils, reference compounds, and digestion products may be a great aid in comprehensive analysis of lipid oxidation and lipolysis.

show abstract

Water cluster calibration reduces mass error in electrospray ionization mass spectrometry of proteins

Cited by 25 publications

References 29 publications

MEMS-Based Nanospray-Ionization Mass Spectrometer

MEMS-Based Nanospray-Ionization Mass Spectrometer

Insights into the Post‐Translational Methylation of Arginine from Studies of Guanidinium–Water Nanodroplets

Liquid Chromatography–Light Scattering Detector–Mass Spectrometric Analysis of Digested Oxidized Rapeseed Oil

Contact Info

Product

Resources

About