1. Introduction
For a host of applications, there is an increasing need to gather detailed chemical INFORMATION about local environments without delays associated with transferring samples to centralized laboratories. These analyses could possibly INFORM us of potential health hazards in water or soil, or be of forensic value in a criminal investigation. Most importantly the desired chemical information could be acquired on site in real time. The environmental sample is commonly a mixture of many components and this makes it difficult to perform exhaustive analysis of the sample as a whole using only spectroscopic methods. One possibility for analysis is to use an array of sensors where the sensors are designed to detect the individual components (such as an array of different ion selective electrodes). While this approach has many advantages, the tailored nature of these systems tends to limit their generic use. A second approach is to separate the sample into its individual components which can then be analysed individually without interference from the other sample components. Depending on the separation method used, it may be possible for the sample to be analysed in a single run using a detector to discover and sometimes to identify species in the sample.