Postcolumn Introduction of an Internal Standard for Quantitative LC−MS Analysis

Choi, Bernard K.; Gusev, and Arkady I.; Hercules, David M.

doi:10.1021/ac990312o

Cited by 77 publications

(52 citation statements)

References 11 publications

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“…In order to keep this review reasonably short, we refer to the following articles which give further information about mass analyzers [11,43,[46][47][48][49]. Strategies for quantitation by MS in proteomics have been reviewed by Lill [50].…”

Section: Mass Spectrometer Typesmentioning

confidence: 99%

Quantitation in capillary electrophoresis-mass spectrometry

2005

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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.

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Section: Mass Spectrometer Typesmentioning

confidence: 99%

Quantitation in capillary electrophoresis-mass spectrometry

2005

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“…Nevertheless, some challenges still remain when performing quantitative LC-MS. An important issue is matrix suppression, a less efficient ionization of the target compound in the presence of other molecules. This phenomenon is well recognized and described in an increasing number of publications [1][2][3][4]. Another complexity in quantitative LC-MS is adduct formation.…”

mentioning

confidence: 90%

“…Another complexity in quantitative LC-MS is adduct formation. Generally, electrospray (ESI) or at- 4 ] ϩ are abundant in the spectra [5][6][7][8][9][10][11]. The exact mechanism of adduct formation still has to be elucidated.…”

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confidence: 99%

“…A first theoretical approach is to ignore the different adduct forms and measure the adduct with the highest response. When measuring only the [M ϩ NH 4 ] ϩ in the presence of other adducts, Li and coworkers obtained a relative standard deviation (RSD) of 17% for a quantitative assay of ginkgolides and bilobalide [5]. Summation of all adduct ions significantly improved the situation to an acceptable RSD of 6%.…”

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confidence: 99%

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Adduct formation in quantitative bioanalysis: Effect of ionization conditions on paclitaxel

Mortier

Zhang

Peteghem

et al. 2004

J. Am. Soc. Mass Spectrom.

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Quantitative analysis of target compounds with liquid chromatography atmospheric pressure ionization mass spectrometry is sometimes hampered by adduct formation. In these situations, cationization with alkali metal ions instead of proton addition is often observed in the positive ion mode. This work studies the process of adduct formation and investigates potential strategies to control this phenomenon. Paclitaxel, a pharmaceutical chemotherapeutic agent, was used as a model compound. Electrospray (ESI), atmospheric pressure chemical ionization (APCI) and sonic spray ionization (SSI) are evaluated and compared. The work was performed on two different instruments, allowing the evaluation of different ionization behavior for different source design for electrospray, if any. Different mobile phase additives were compared, including acetic acid, formic acid, ammonium formate, and a range of primary amines. Continuous infusion was used for a fast screening, to detect optimal conditions. These were then further investigated in detail by LC-MS. The results indicate that electrospray is the more sensitive interface for this compound on the investigated apparatus. Unacceptable quantitative data were acquired without additives in the mobile phase. Generally, additives increased the reproducibility significantly. A response of mainly one ion was achieved with dodecylamine/acetic acid and acetic acid/sodium acetate. The data also point out the importance of evaluating adduct formation for compounds prone to this phenomenon during method development, especially in view of accurate quantitation. (J Am Soc Mass Spectrom 2004, 15, 585-592)

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“…However, one of the main drawbacks of LC-MS/MS methods is the matrix effect in the ionization source, producing an inhibition or enhancement of the MS signal [25 -27]. Different possibilities to compensate for this desirable effect have been proposed as: (i) the use of the labeled IS [28] being the most easy and convenient way although with the limitations of the commercial availability, price, and purity of the reference standard; (ii) simple dilution of the extract to give a signal comparable to that of standard solutions [29], with the drawback of the unavoidable loss in sensitivity; (iii) quantification with matrix-matched standard calibration [30 -32], which compensates the matrix effect, with the drawback of finding a real representative blank sample and assuming that all samples present similar matrix effects. In some cases, a combination of two of these approaches is applied, for example, dilution of sample extract and matrix-matched standard calibration [33 -35].…”

Section: Optimization Of Sample Preparationmentioning

confidence: 99%

Rapid quantification of sucrose esters in oriental tobacco by liquid chromatography‐ion trap mass spectrometry

Ding

Xie

Zhao

et al. 2007

J of Separation Science

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A rapid and sensitive LC-MS/MS method was developed for the quantitative determination of sucrose esters (SEs) in Oriental tobacco samples. The sample preparation involved a 10-min sonication extraction procedure with acetone and five-fold dilution of the extract with methanol. The experiment was carried out in positive ion mode by ESI IT mass spectrometer. Because of lack of authentic standards of SEs, sucrose octa-acetate (internal standard, IS) was used as a surrogate to validate the proposed method. Matrix-matched standard calibration was used for quantification of IS in the spiked samples. Under optimized MS/MS conditions, an LOQ of 3.9 microg/g was achieved for IS, with an LOD of about 1.2 microg/g. Recoveries for IS were 95-97%. Among 19 monitored SEs, the contents of 11 SEs had RSDs lower than 13.7%. The method, with very little sample handling and good sensitivity, was applied to the rapid quantification of SEs in four Oriental tobacco samples. It appears that the sum of contents of the five SEs with MW 650, 664, and 678 Da occupied approximately 80% of the total content of SEs.

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Postcolumn Introduction of an Internal Standard for Quantitative LC−MS Analysis

Cited by 77 publications

References 11 publications

Quantitation in capillary electrophoresis-mass spectrometry

Quantitation in capillary electrophoresis-mass spectrometry

Adduct formation in quantitative bioanalysis: Effect of ionization conditions on paclitaxel

Rapid quantification of sucrose esters in oriental tobacco by liquid chromatography‐ion trap mass spectrometry

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