Browsing by Author "Rönkkö, Tuukka"

The literature part of this thesis consists of a review of recently introduced forms of solid phase microextraction (SPME): thin film microextraction (TFME), in-tube solid phase microextraction(IT-SPME) and the closely related techniques of capillary in tube adsorption trap/solid phase dynamic extraction (INCAT/SPDE). The experimental part covers the study of reagents for on-fiber derivatization of low molecular weight aliphatic amines in atmospheric concentrations. In TFME a thin film of sorbent is used for extraction instead of a rod-like sorbent as in fiber-SPME. This increases analyte uptake and capacity compared to fiber-SPME, making TFME suitable for non-equilibrium extraction. TFME is used with both gas and liquid chromatography, although the large size of the film presents problems in desorption, especially in gas chromatography. Common applications of TFME are environmental monitoring and in vivo extraction. IT-SPME is a dynamic type of SPME most often coupled with liquid chromatography, in which a liquid sample is pumped through an extraction capillary. It is relatively easily automated with most autosamplers. In the most common form a sorbent is coated on the inside walls of the capillary. Recently, packed types of IT-SPME have been introduced, which can achieve very high extraction efficiencies. In addition, sorbent materials which change their properties according to environmental factors such as temperature, potential and magnetic field seem promising for future development. INCAT/SPDE utilizes internally coated metal needles for extraction. Although similar to IT-SPME, it is used for sampling gaseous compounds by pumping them through the needle. Desorption and analysis is usually performed with a gas chromatograph. INCAT/SPDE has some advantages over fiber-SPME, such as larger sorbent volume and robustness. However, it is currently limited to only polydimethylsiloxane-based sorbents, which limits possible applications. In the experimental part, the possibilities of using allyl isothiocyanate, pentafluorobenzaldehyde(PFBAY) and pentafluorobenzyl chloroformate (PFBCF) in simultaneous extraction and on-fiber derivatization of low molecular weight aliphatic amines were explored. Separation and analysis was performed with gas chromatography-mass spectrometry. Allyl isothiocyanate did not derivatize the analytes. On-fiber derivatization with PFBAY was successful for both ethylamine and methylamine, but the concentrations required to observe signal from the derivatives were too high to use PFBAY for air samples. PFBCF was identified as the most promising reagent, working for both dimethylamine and ethylamine. It was also possible to construct a calibration function for gaseous dimethylamine.