Chapter 5. Greening Sample Preparation: New Solvents, New Sorbents

Sample preparation is still identified as the bottleneck of many modern analytical procedures owing to the time-demanding nature of many of the treatment protocols in use. Sample treatment is also considered responsible for a large part of the analytical inaccuracy of analytical methodologies because of the highly manipulative nature of most of these treatments. It is also one of the main limitations when trying to develop green analytical procedures because of the large amounts of reagents and energy consumption typically associated with most of the conventional sample preparation procedures. However, the efforts made in recent decades in this active research field are starting to improve the situation. Today, a plethora of miniaturized techniques have been commercialized for the treatment of liquid (or dissolved) samples. When combined with an appropriate state-of-the-art separation-plus-detection technique, accurate analyte determination is possible even if only a very small amount of sample (i.e. a few mg or mL) is used for the analysis. More importantly, many of these techniques allow sample preparation to be completed in a short time with minimal reagent and energy consumption and with a significant reduction in the amounts of waste generated. In recent years, initial limitations identified in some of these miniaturized solvent-based techniques have started to be circumvented by the incorporation of new non-toxic extraction media as extractants. Similarly, sorbent-based techniques have benefited from advances in the field of engineered materials and nanotechnology by the incorporation of novel sorbents with tuned physicochemical properties for enhanced extraction efficiency and selectivity. Using the analysis of trace organic components in food and environmental matrices as case studies, this chapter reviews the current state-of-the-art in the field of sample preparation.