Semi-automated hollow-fibre membrane extraction, a novel enrichment technique for the determination of biologically active compounds in water samples

An automated hollow fibre membrane extraction technique was developed for the GC–MS determination of pharmaceutical and endocrine disrupting compounds in water samples. Enrichment was carried out inside a porous polypropylene hollow fibre membrane, which separated the aqueous and organic phases and regulated the transfer of analytes. n-Octanol placed inside the hollow fibre was used as the acceptor solution. A water–solvent ratio of about 300:1 was used to concentrate the analytes. After 1 hour’s extraction of the water sample under magnetic stirring, 1 μl of the n-octanol phase was automatically injected from the hollow fibre into the GC–MS. Development work included examining the influence of different sample matrices, volumes, extraction times and extraction solvents. The detection limits, linearity and standard deviations of the method were determined using drugs such as ibuprofen, phenazone and carbamazepine as well as the endocrine disrupting compounds, technical nonylphenols, bisphenol A, 17α-ethinylestradiol and tonalide by way of example.