Chemistry Reference
In-Depth Information
7
Green Analytical Chemistry Approaches
in Sample Preparation
Marek Tobiszewski, Agata Mechli ´ska and Jacek Namie´nik
Department of Analytical Chemistry, Chemical Faculty, Gdansk University of Technology (GUT),
Gdansk, Poland
This chapter presents environmentally friendly solutions for sample preparation. Attention is focused
on extraction techniques and the minimization of organic solvent consumption, as the large quantities
used in analytical laboratories are a pressing environmental problem. Solventless sample preparation
techniques, alternative solvents, mediated extractions are discussed. The principle of each technique is
briefly described, together with its main areas of application and some of its analytical parameters.
7.1
About sample preparation
Rapid advances in technology have led to the design of highly sensitive analytical instruments. Unfortunately
however, most of them are unable to directly handle samples with a complex matrix composition. Nevertheless,
modern chemical analysis requires the determination of certain target compounds at trace levels. To meet
these demands, a sample preparation step is performed. On the one hand, the sample matrix is converted to
one that is easily handled by analytical apparatus; on the other, analytes are concentrated to improve the
method's sensitivity.
Nowadays, most determinations of trace organic compounds involve chromatographic techniques. Since
chromatographic columns are sensitive to impurities often present in the matrix, this should be converted to
one of simple composition. Most pre-chromatographic sample preparation techniques involve the extraction
of analytes. Liquid-liquid extraction (LLE) is one of the oldest of these techniques, but it is time-consuming,
