Matrix Solid Phase Dispersion and Online Coupling for the Analysis of Environmental Samples

This licentiate thesis is based on two papers that describe two original methods for analysing environmental pollutants. In both cases samples were extracted by onor off-line Matrix Solid Phase Dispersion (MSPD), then target analytes were separated from potentially interfering matrix components and analysed by Liquid Chromatography–Mass Spectrometry (LC-MS). Hot water and a small volume of methanol were used as extraction solvents, minimising analytical costs. Paper I describes a novel, inexpensive, rapid and environmentally friendly procedure for the selective extraction of carbamate insecticides in vegetables and fruits involving MSPD for sample preparation (using heated water as the extraction solvent), followed by LC-MS to identify and quantify the analytes. Heated water proved to be an efficient and selective extraction phase for this purpose. Just a simple acidification and filtration of the resulting extracts are required before injection into the LC-MS system. Matrix effects resulting from the co-extraction of endogenous compounds eluting in the first part of chromatographic runs were repressed by this procedure, improving the chromatography separation. In the study described in Paper II C8 Empore solid phase extraction (SPE) membranes were used to sample airborne organophosphate esters, which were trapped very efficiently by these silicaderivatized membranes. The analytes were completely desorbed from the membrane with methanol, by pumping water through the extraction cell on-line using a High Pressure Liquid Chromatography (HPLC) pump. The addition of water to the mobile phase, prior to the analytical HPLC column ensured that the analytes were refocused before analysis. The possible effects of the presence of particulate matter during the extraction step were investigated by spiking Empore Disks with NIST reference standard material (urban dust, SRM 1649a). No breakthrough was observed during 24 hours sampling at a flow rate of 10 l/min (14.4 m total sampling volume), and no degradation or losses of analytes were observed after 5 days at room temperature.