Modern mass spectrometric techniques applied to occupational hygiene analysis.

FORD, Michael James. (2002). Modern mass spectrometric techniques applied to occupational hygiene analysis. Doctoral, Sheffield Hallam University (United Kingdom)..

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The identification of chemical hazards is of significant importance in occupational hygiene. The concentration at which a chemical substance may be regarded as a hazard may be very low and as a result of this the demands on analytical techniques to determine the presence of a chemical substance can be great. Mass spectrometry is an analytical technique with a broad range of applications, described as the universal detector; the technique offers high sensitivity and high selectivity. Althomugh an established technique in many areas only limited applications have been reported in the field of occupational hygiene analysis.The aim of this work was to apply modem mass spectrometric techniques to analyse samples arising from occupational hygiene monitoring. Liquid Chromatography/Mass Spectrometry (LC/MS) was used with Electrospray Ionisation (ESI) and Atmospheric Pressure Chemical Ionisation (APCI). Nanospray ionisation was used for the direct infusion analysis of isocyanate samples. Matrix assisted Laser Desorption/Ionisation (MALDI) has been demonstrated as an ionisation technique suitable for application to occupational hygiene sample analysis. Tandem mass spectrometry (MS/MS) was used where necessary to identify unknown species. Benzalkonium Chloride (BAC) has biocidal properties and for this reason the substance is used in many products such as in-can preservatives and ophthalmic cleaning systems. The phenyl substituent of BAC facilitates detection by spectrophotometric methods. Other quaternary ammonium compounds, that have no chromaphore, are used in preparations also containing BAC. The detection of these compounds can be a problem. In this work an LC/ESI/MS method is presented for the analysis of mixtures of BAC and other non-chromaphoric quaternary ammonium compounds. Excellent limits of detection were achieved e.g., 3 for the C2 homologue of BAC. MS/MS and cone voltage dissociation techniques were used to identify an unknown quaternary ammonium compound.Iodopropynylbutylcarbamate, a wood treatment agent with fungicidal properties, was analysed using LC/MS with APCI and ESI techniques. The effect of the cone voltage on the ionisation efficiency was studied, as were the effects of the wood treatment formulation matrix. Limits of detection of 3.19 using APCI and 8.95 using ESI were calculated.Isocyanates are the number one cause of occupational asthma in the U.K. 1-(2-methoxyphenyl)piperazine derivatised isocyanate monomers and prepolymers were studied using LC/ESI/MS, nanospray and MALDI mass spectrometric techniques. Tandem mass spectrometry was used to facilitate structural elucidation of several derivatised prepolymeric isocyanate species.The surfactant composition of a commercial sheep dip formulation was analysed using MALDI and LC/ESI/MS. The major surfactant constituent of the sheep dip formulation was identified as ethoxylated phenol. Mass spectrometry is shown to be a technique well suited to the analysis of nonionic surfactants.

Item Type: Thesis (Doctoral)
Thesis advisor - Clench, Malcolm [0000-0002-0798-831X]
Additional Information: Thesis (Ph.D.)--Sheffield Hallam University (United Kingdom), 2002.
Research Institute, Centre or Group - Does NOT include content added after October 2018: Sheffield Hallam Doctoral Theses
Depositing User: EPrints Services
Date Deposited: 10 Apr 2018 17:19
Last Modified: 03 May 2023 02:05

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