You are currently involved in developing environmentally friendly extraction procedures for environmental applications? Why is this type of research important?

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Thus, the development and adoption of environmentally friendlier analytical techniques, particularly in sample preparation, pretreatment and extractions, should be a primary aim of those working in environmental analysis. It is important because we must have the credibility to practice what we are preaching to the public at large and the decision-makers. As a community scientists should try to minimize — and, if possible, completely eliminate — the emission of potentially harmful chemicals into the environment.

Our primary interest is in the development and applications of sample preparation procedures that require minimal amounts of solvents, reagents and materials. These are microscale or miniaturized techniques so they are environmentally benign and chemically sustainable (in the sense that there is very little, if any, wastage). A major focus is the application of these techniques to environmental samples, particularly aqueous matrices.

I think environmental analysis is perhaps the most common application of analytical chemistry, so it seems a desirable area to develop techniques for. Another important philosophy that I have about this is that the procedures should be simple enough to learn and to use, so that those with access to basic tools and apparatus can apply them to perform useful and meaningful analytical chemistry. Of course, there are some esoteric techniques that appear to be very exciting, but they are not globally accessible to the general analytical community. I think there are a lot of scientists in the less developed regions of the world who would like to plug into the global grid but are unable to do so because the costs are prohibitive. Simple and affordable procedures allow such accessibility.

Can you describe the techniques you have developed, the main obstacles that you had to overcome and the benefits of these over existing techniques?

I did not realize it previously, but it seems that our group first coined the term "liquid-phase microextraction" (LPME) that is now widely used in the literature. In our original work, the idea of using this term was to represent a procedure that used very small amounts (low microlitre amounts) of solvent for extraction from water samples. Solid-phase microextraction (SPME), a solventless extraction and preconcentration technique developed by Pawliszyn's group at the University of Waterloo, Canada, was already well-known (and commercially successful) then, and it seemed to us it was natural to try and have a complementary counterpart in which small volumes of solvent were involved.

This is basically liquid–liquid extraction, probably still the most common extraction procedure for water samples, but at a miniaturized scale. (Note that I don't use "miniaturized" to mean dimensions as applied to the microfluidics field. In our context, we do not need any special fabrication or handling tools.) I must mention and emphasize that, in our work, we were inspired by the early research on solvent-minimized or organic drop-based extraction by Cantwell from the University of Edmonton, Canada and Dasgupta who worked at the Texas Technical University, Lubbock, USA at the time, as well as Pawliszyn's work on SPME.