Adequate sampling, an important step towards reliable decisions based on analytical results

Abstract

The efforts spent on judgments of how to perform sampling are often small compared to other steps in the analytical procedure. As a result decisions may be based on irrelevant results. If the sampling is intended to provide information how to reduce and control environmental pollution, it is important to design the sampling strategy according to scientific principles. Sampling will be discussed in relation to determinations of organic as well as inorganic species in different types of polluted matrices, .e.g. water, sediments and air. Examples will be taken from our own research projects about treatment processes for contaminated matrices. Accurate sampling involves a basic planning including objectives, cost effectiveness versus the budget, variability of contamination leading to statistical considerations, site accessibility and robustness of the used devices. A strategy for the sampling, often in a form of a scheme, is needed. The Laqua Protocol developed within our research projects will be presented. This protocol is flexible and dynamic and can be altered and optimized based on the demands at the individual sampling site. Sampling of complicated matrices often creates problems with interfering agents and breakdown of unstable analytes. In this type of samples the concentrations of analytes are generally several orders of magnitudes lower than the concentrations of major constituents in the sample. Accordingly the advantages of an early work-up, preferably in connection with a sampling procedure, is paid especially attention