Colibacteria in water. To these means, (a) a prototype of a novel online sampling set-up is built, using magneticnanoparticle labelling, (b) the transport of magnetically labelled E.Coli bacteria to the detection chamber is automated by controlled electro-magnets, (c) the optical detection is performed using fluorescent labelling, (d) the whole set-up is automatically flushed and readied for the next water sample.