Novel approaches to the measurement of complex atmospheric VOC mixtures using proton transfer reaction mass spectrometry

Blenkhorn, Daniel John (2019). Novel approaches to the measurement of complex atmospheric VOC mixtures using proton transfer reaction mass spectrometry. University of Birmingham. Ph.D.

Blenkhorn19PHD.pdf
PDF
Download (3MB)

Abstract

Proton Transfer Reaction – Mass Spectrometry (PTR-MS) is a soft chemical ionisation mass spectrometry technique frequently applied to measurement of volatile organic compound (VOC) abundance.

The overarching aim of this thesis is to improve the quantification of compounds that have proved difficult or even impossible to separate or to quantify, through advanced understanding of the detection and ionisation mechanisms and developments in the instrumental design and operation of PTR-MS for deconvolution of mixtures.

A new method for the preparation and use of diffusion tube methods as gas standards is reported. Detailed investigation of the ion-molecule reactions with chloroalkanes, chloroalkenes and other atmospherically important molecules, such as isoprene / 2-methyl-3-buten-2-ol, benzene / ethylbenzene / o,m,p-xylene and methyl vinyl ketone / methacrolein were undertaken to determine the ion- molecule reaction mechanisms, allowing quantification of isomeric species through understanding of the reaction products and novel approaches to the switching of the reduced electric field strength (E/n).

The modification of instrumental parameters of PTR-MS were investigated further for the quantification of semi volatile compounds (SVOCs) and more specifically, polycyclic aromatic hydrocarbons (PAHs). Use of a radio frequency (RF) ion funnel and high temperature instrumentation allowed for sub nanogram limits of detection for many PAHs, including Benzo[a]pyrene.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):