Methamphetamine: Airborne analysis and oxidative destruction

This thesis investigates two chemical aspects of the remediation of former clandestine methamphetamine laboratories: developing methods for detecting airborne methamphetamine with short (ca. 20 min) sampling times, and oxidation of methamphetamine as a possible decontamination method. Dynamic solid phase microextraction (SPME) had been previously used to detect μg m-3 concentrations of airborne methamphetamine at former clandestine laboratories, where surface methamphetamine concentrations exceeded 60 μg/100 cm2. The current study found that for sampling times under 20 min, relative humidity values up to 70% did not influence the sorption of methamphetamine for dynamic SPME sampling. A comparison of the sorption abilities of polydimethylsiloxane (PDMS) and carboxen/divinylbenzene/polydimethylsiloxane (CAR/DVB/PDMS) fibres revealed that the PDMS fibre was twice as effective at sampling methamphetamine, under identical conditions. Capillary microextraction (CME), a high-surface area microextraction technique that has been used for sampling volatile organic compounds, was investigated as a more sensitive alternative to dynamic SPME sampling. CME devices were used to sample methamphetamine vapour (0.42-4.2 μg m-3) and analysed using GC/MS. The CME-GC/MS technique was found to be over 30 times more sensitive than the original dynamic SPME-GC/MS method. The CME devices were not affected by changes in relative humidity, and could be stored for up to 3 days post-sampling, without any loss of analyte. We demonstrated that on-sorbent derivatisation of methamphetamine with pentafluorobenzyl chloroformate could be conducted using the CME devices, improving both the intra-device variability and the detection limit of the analysis. Finally, four peroxide-based oxidations of methamphetamine were examined as potential methods for decontamination, and the reaction products were identified. 10% hydrogen peroxide, in the presence of an Fe-TAML catalyst, was the most effective, decomposing >99% of the methamphetamine into products including ii phenyl-2-propanone and benzaldehyde. BioOxygenÒ Chem-Decon, a commercial proprietary formulation, was effective in the removal of 93% of the methamphetamine, with the major identified product being phenylacetone oxime. 10% hydrogen peroxide, and 15% alkalised hydrogen peroxide were less effective under the conditions used, oxidising less than half the methamphetamine into products that could not be identified using our GC/MS and LC/MS protocols.

Name thesis:degree_name

PhD

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Forensic Science

Grantor dc:publisher

ResearchSpace@Auckland

Year dc:date.issued

2018

Author dc:creator

• Nair, Mansa

Advisors dc:contributor.advisor

• Miskelly, G
• Fedrizzi, B

Statement dc:rights

• Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher.

Licence dc:rights.uri

• https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm

Handle dc:identifier.uri

https://hdl.handle.net/2292/40750

OAI identifier oai:identifier

oai:researchspace.auckland.ac.nz:2292/40750