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1A - Environmental analytical methods (MOP/10) Solid-phase-extraction, sequential elution and derivatisation of acidic pharmaceuticals and estrogens from water samples for GC/MS-determination. Hühnerfuss, Heinrich1, Kuhlmann, Jan1, Weigel, Stefan1, 1 University of Hamburg, Institute of Organic Chemistry, Hansestadt, Hamburg, Germany ABSTRACT- Many anthropogenic compounds that have recently been identified in aquatic systems are polar organic molecules. For example, pharmaceuticals, personal care products and transformation products are a new and important class of environmental contaminants. Due to their polarity many of these substances are well soluble in water and less volatile, properties excluding the direct application of liquid/liquid-extraction and GC-separation for analytical determination. In order to make use of the high sensitivity and simple technique of GC/MS, however, investigations were carried out to establish an adequate method for the determination of different classes of analytes from water. A sampler was constructed allowing the sampling of various amounts of water up to 2,5 L for trace-analytical purposes. Two types of on-line glass-fibre filtration units were built to ensure sufficient flow rates during solid-phase-extraction (SPE) of samples with a high particle load. The following representative compounds served for spiking experiments: clofibric acid, ibuprofen, ketoprofen, diclofenac, triclosan, estrone, estradiol, ethinylestradiol, mestranol. Two polymeric sorbents were compared for SPE. A sequential elution led to three fractions of rising polarity. The medium polar fraction was silylated with N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA), whereas the polar fraction was derivatised with methylchloroformate (MCF). A proper separation of steroids from the acidic compounds was achieved with Bakerbond SDB 1 sorbent, with recovery rates of 93 to 104 % for the steroids, whereas those of the acidic compounds were 36 to 53 %. Using Oasis HLB for SPE increased the recovery rates of the acidic compounds, but caused a loss of triclosan in the acidic fraction. Results for tapwater, surface water and sewage effluent are presented. Key words: sorbents, filtration, derivatisation, recovery |
