Sample preparation for environmental analysis

Sample preparation continues to be an important step in environmental analysis and a lot of progress has been made in the last decade toward the development of faster, safer, and more environmentally friendly techniques for sample extraction and extract clean up prior to instrumental analysis. This article focuses on the state of the art in sample preparation, particularly in the area of supercritical fluid extraction, microwave-assisted extraction, accelerated-solvent extraction for solid matrices, and both solid-phase extraction and solid phase microextraction for aqueous matrices. Driven by the need for faster, cheaper, and more sensitive analytical methods, advances in sample preparation have included not only automation but many developments in coupling sample preparation with instrumental analysis (e.g., supercritical fluid extraction coupled with immunoassays). Examples are presented for extraction of polynuclear aromatic hydrocarbons, organochlorine pesticides, polychlorinated biphenyls, phenolic compounds, triazine and chlorophenoxy acid herbicides, and organotin and organomercury compounds from solid matrices with supercritical carbon dioxide and modified supercritical carbon dioxide as well as organic solvents under microwave irradiation. Emerging trends in sample preparation such as in situ derivatization/extraction of analytes from solid matrices and solventless extraction techniques such as solid-phase microextraction are presented.