Chapter 4 - Sample processing

Abstract

While this book focuses on emerging methods for the detection of waterborne pathogens, this chapter is devoted to sample processing which plays a key role in the ultimate success of any detection technology. Many of the techniques discussed in the following chapters process μL to a few mL, whereas it may be necessary to sample hundreds of mL to thousands of litres. Large sample volumes are required to gain a more representative sample of a large water volume as well as to increase the likelihood of detecting pathogens present at very low concentrations. Sampling of a large volume over a period of time will to some extent compensate for some spatial and temporal variations in pathogen distribution. Additionally, the concentration aspect of sample processing is necessary to bring the pathogen concentration into the detection limit of monitoring methods. Furthermore, while some techniques would detect single pathogens, the time required for a single pathogen in a large volume of water to reach the detection area/surface could be prohibitively long. Sample processing is also important for isolation of the pathogen of interest and for the removal of interferents which could disturb the detection process. The nature of problematic interferents varies with the final monitoring technique employed and therefore different sample processing methods may be required depending on the full scheme of detection.