Proton Transfer Reaction Mass Spectrometry Principles And Applications Pdf


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Proton-transfer-reaction mass spectrometry PTR-MS is an analytical chemistry technique that uses gas phase hydronium reagent ions which are produced in an ion source. Commercially available PTR-MS instruments have a response time of about ms and reach a detection limit in the single digit pptv or even ppqv region.

Proton transfer reaction- mass spectrometry PTR-MS is a new and emerging technique for the measurement and monitoring of volatile organic compounds VOCs at low concentrations in gaseous samples in more-or-less real time. Utilising chemical ionisation , it combines the desirable attributes of high sensitivity and short integration times with good precision and accuracy. Recently it has been exploited in applications related to atmospheric science. Here, the principles of operation of the PTR-MS are described, its advantages and disadvantages discussed, its inherent uncertainties highlighted, some of its uses in atmospheric sciences reviewed, and some suggestions made on its future application to atmospheric chemistry. If you are not the author of this article and you wish to reproduce material from it in a third party non-RSC publication you must formally request permission using Copyright Clearance Center.

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Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. Proton Transfer Reaction — Mass Spectrometry PTR-MS is a sensitive, soft ionisation method suitable for qualitative and quantitative analysis of volatile and semi-volatile organic vapours.

The raw data supporting the conclusions of this manuscript will be made available by the authors, without undue reservation, to any qualified researcher. Soft chemical ionization mass spectrometric techniques, such as proton transfer reaction mass spectrometry PTR-MS , are often used in breath analysis, being particularly powerful for real-time measurements. To ascertain the type and concentration of volatiles in exhaled breath clearly assignable product ions resulting from these volatiles need to be determined. This is difficult for compounds where isomers are common, and one important class of breath volatiles where this occurs are ketones. Of particular interest is to determine if ketone isomers can be distinguished without the need for pre-separation by manipulating the ion chemistry through changes in the reduced electric field. An additional issue for breath analysis is that the product ion distributions for these breath volatiles are usually determined from direct PTR-MS measurements of the compounds under the normal operating conditions of the instruments. Generally, no account is made for the effects on the ion-molecule reactions by the introduction of humid air samples or increased CO 2 concentrations into the drift tubes of these analytical devices resulting from breath.

The sensitivity of PTR-ToF-MS also depends on the ability to effectively focus and transmit ions from the relatively high-pressure drift tube DT to the low-pressure mass analyzer. IF consists of a series of electrodes with gradually decreasing orifice diameters. Radio frequency RF voltage and direct current DC electric field are then applied to the electrodes to get the ions focused. We investigated the effect of the RF voltage and DC field on the sensitivity of a pattern of VOCs including hydrocarbons, alcohols, aldehydes, ketones, and aromatic compounds. In a proof-of-concept study, the instrument operating both as normal DT DC-mode and at optimal IF conditions RF-mode was applied for the breath analysis of 21 healthy human subjects.

Proton-transfer-reaction mass spectrometry

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Proton Transfer Reaction Mass Spectrometry: Principles and Applications

Soft chemical ionization mass spectrometric techniques, such as proton transfer reaction mass spectrometry PTR-MS , are often used in breath analysis, being particularly powerful for real-time measurements. To ascertain the type and concentration of volatiles in exhaled breath clearly assignable product ions resulting from these volatiles need to be determined. This is difficult for compounds where isomers are common, and one important class of breath volatiles where this occurs are ketones.

Proton Transfer Reaction Mass Spectrometry Principles and Applications

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