Jana St'avova

Date of Award

12-12-2011

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

First Advisor

Alena|Seames, Wayne Kubatova

Abstract

Accurate analytical methods are needed to evaluate the quality of newly developed biofuels. In this dissertation, a method employing gas chromatography with simultaneous flame ionization and mass spectrometry detection (GC-FID/MS) was developed for detailed characterization of complex biofuel intermediates generated upon crop oil pyrolysis. An efficient separation of individual compounds was achieved using a cryogenic cooling and single temperature gradient of 2.5°C min-1. Two standard mixtures were designed for accurate identification. A programmed temperature vaporizer and a designed calibration standard (20 representative components) minimized the compound discrimination, and thus enabled accurate quantification of over 250 species. Besides hydrocarbons, the unidentified and unresolved aggregate components of the complex mixture were also quantified. Several derivatization agents used for esterification (BF3/butanol), and trimethysilylation, [trimethylsilyl-N-N-dimethylcarbamate and N, O-bis(trimethylsilyl)trifluoroacetamide] were evaluated to determine a broad range of C1–C18 monocarboxylic and C 2–C14 dicarboxylic acids. The lowest limits of detection (LODs) and the best product stability for the majority of compounds below 10 pg were obtained when using BF3/butanol. Less labor-intensive trimethylsilylation with BSTFA was employed for biofuel intermediate samples. The derivatization yielded comparable LODs to those of butyl esters. Unlike in other reported studies, mass balance was successfully closed for tested biofuel intermediates as well as JP-8 fuel. Wood is another challenging matrix requiring a thorough analytical method development, particularly when targeting fungicides and insecticides used as preservatives. Fungicides and insecticides are commonly used preservatives to protect wood products against microbiological degradations. Currently, there is a lack of analytical methods addressing the quantitative determination of a wide range of wood preserving species in complex wood matrices. In this dissertation, a reliable method was developed for the quantitative determination of a mixture of wood preserving agents with differing chemical structures: tebuconazole, propiconazole, 3-iodo-2-propynyl butylcarbamate (IPBC), and permethrin (PER), in complex pine wood. More accurate and less labor-intensive Soxhlet extraction with acetone achieving 80–100% analyte recoveries was preferred over multiple-stage sonication. A solid phase extraction method for triazoles was adapted to allow for a separation of IPBC and PER from the wood matrix, with LODs within 0.07–0.21 ng/g for triazoles and 1.7–6.0 ng/g for IPBC and PER. A gradient distribution of analytes determined in commercially treated wood demonstrated the necessity of the developed method when evaluating the treatment technique.

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