The coupling of gas and liquid chromatography with mass spectrometry

Abian, Joaquín

doi:10.1002/(sici)1096-9888(199903)34:3<157::aid-jms804>3.0.co;2-4

Cited by 112 publications

(77 citation statements)

References 71 publications

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“…ESI and APCI are also collectively referred to as API techniques. 5,14,19 In contrast to electron ionization (EI), both ESI and APCI afford little or no fragmentation of the analyte; thus, they are referred to as 'soft' ionization techniques. A brief description of the ionization processes involved in ESI and APCI as well as an overview of the current status of enantioselective chromatography in conjunction with ESI-and APCI-MS are presented below.…”

Section: Basic Modules Of a Mass Spectrometermentioning

confidence: 99%

“…10,19 In combination with microcapillary LC, flow rates as low as 20-1,000 nl/min are amenable. 5,14 Since ESI is concentration-sensitive, an improvement in ionization efficiency and ion sampling is realized at lower flow rates. Nonetheless, flow rates of up to 1.0-1.5 ml/min for direct introduction into ESI interface can be achieved using the turbo ion-spray (TISP) or pneumatically assisted electrospray technology.…”

Section: Electrospray Ionizationmentioning

confidence: 99%

“…Currently, a wide variety of ESI interface designs are available by several vendors, such as Finnigan, Sciex, Micromass, Hewlett-Packard, JEOL, Shimadzu, and Bruker. 5,19,21 …”

Section: Electrospray Ionizationmentioning

confidence: 99%

“…For example, in the positive-ion mode the energetic electrons start a sequence of reactions with the nebulizing gas (typically nitrogen) giving rise to nitrogen molecular ions. 5,12,14 Depending on the composition of the HPLC mobile phase, ions such as [H 2 O+H] + , [CH 3 OH+H] + , [NH 3 +H] + , and/or [CH 3 CN+H] + are formed via a series of ion-molecule reactions with the nitrogen molecular ions. Subsequently, additional ionization is initiated by exothermic proton transfers from the protonated solvent ions to the neutral analyte molecules yielding [analyte+H] + , [analyte+CH 3 OH+H] + , [analyte+NH 3 +H] + ions, etc.…”

Section: Atmospheric Pressure Chemical Ionizationmentioning

confidence: 99%

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Use of atmospheric pressure ionization mass spectrometry in enantioselective liquid chromatography

2001

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Recent advances in mass spectrometry have rendered it an attractive and versatile tool in industrial and academic research laboratories. As a part of this rapid growth, a considerable body of literature has been devoted to the application of mass spectrometry in studies involving enantioselectivity, molecular recognition, and supramolecular chemistry. In concert with separation techniques such as capillary electrophoresis and liquid chromatography, mass spectrometry allows rapid characterization of a large array of molecules in complex mixtures. A majority of these findings have been made possible by the introduction of 'soft-ionization' techniques such as electrospray ionization interface. Other techniques such as atmospheric pressure chemical ionization mass spectrometry have been widely used as a rugged interface for quantitative liquid chromatography-mass spectrometry. Herein, we present a brief overview of the above techniques accompanied with several examples of enantioselective capillary electrophoresis- and liquid chromatography-mass spectrometry in drug discovery and development. Although the emphasis of this article is on quantitative enantiomeric chromatography-mass spectrometry, we envisage that similar strategies are adaptable in qualitative studies.

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Section: Basic Modules Of a Mass Spectrometermentioning

confidence: 99%

Section: Electrospray Ionizationmentioning

confidence: 99%

“…Currently, a wide variety of ESI interface designs are available by several vendors, such as Finnigan, Sciex, Micromass, Hewlett-Packard, JEOL, Shimadzu, and Bruker. 5,19,21 …”

Section: Electrospray Ionizationmentioning

confidence: 99%

Section: Atmospheric Pressure Chemical Ionizationmentioning

confidence: 99%

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Use of atmospheric pressure ionization mass spectrometry in enantioselective liquid chromatography

2001

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“…Secondly, there is an opportunity in each stage to improve the ion density, by using ion optical elements such as quadrupole ion guides [32,33], wire ion guides [34,5 35], stacked ring ion guides [36,37] or electrostatic discriminators [38] to transfer ions while neutrals are pumped away. Reviews of ESI-MS interfaces can be found in [39,40].…”

Section: Introductionmentioning

confidence: 99%

MEMS-Based Nanospray-Ionization Mass Spectrometer

Wright¹,

Syms

Moseley³

et al. 2010

J. Microelectromech. Syst.

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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...

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Liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry enantiomeric separation ofdl-threo-methylphenidate, (Ritalin®) using a macrocyclic antibiotic as the chiral selector

Ramos

Bakhtiar

Majumdar

et al. 1999

Rapid Commun. Mass Spectrom.

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Vancomycin, a macrocyclic antibiotic, is an amphoteric glycopeptide produced by Streptomyces orientalis which has proven to be a viable chiral selector for high performance liquid chromatograph (HPLC) (D. W. Armstrong, Y. Tang, S. Chen, Y. Zhou, C. Bagwill and J-R. Chen, Anal. Chem. (1994; 66: 1473). While it is related to other glycopeptide antibiotics, vancomycin has a number of unique structural features, including 18 stereogenic centers, five aromatic rings, and two side chains one of which is a carbohydrate dimer. Therefore, a vancomycin-based stationary phase appears to be multimodal in that it can be utilized in both normal-phase and reversed-phase liquid chromatography. Consequently, the enantiomeric separation may be operative via several mechanisms, including pi-pi complexation, dipole stacking, inclusion, hydrogen bonding, or combinations of these interactions. LC/MS/MS is a powerful tool for quantitative analysis when evaluated on the basis of speed, specificity, reliability and sensitivity. For these reasons, the present paper explored the feasibility of bonded macrocyclic glycopeptide phases for chiral LC/MS/MS quantitative analysis. Methylphenidate was used as a model compound. A rapid chiral bioanalytical method (<7.5 min) for the determination of the enantiomers of methylphenidate was developed. A lower limit of quantification (LLOQ) of 87 pg/mL was attained for the human plasma assay. This is to our knowledge the first example of enantioselective reversed-phase LC/MS/MS for methylphenidate. The chiral column was relatively cost effective and exhibited excellent performance with no separation deterioration observed after approximately 2500 injections.

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The coupling of gas and liquid chromatography with mass spectrometry

Cited by 112 publications

References 71 publications

Use of atmospheric pressure ionization mass spectrometry in enantioselective liquid chromatography

Use of atmospheric pressure ionization mass spectrometry in enantioselective liquid chromatography

MEMS-Based Nanospray-Ionization Mass Spectrometer

Liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry enantiomeric separation ofdl-threo-methylphenidate, (Ritalin®) using a macrocyclic antibiotic as the chiral selector

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