Modern Techniques of Sample Preparation for Determination of Organic Analytes by Gas Chromatography

The majority of techniques currently applied for isolation/enrichment of organic analytes from gaseous and liquid samples are based on extraction and utilize solid absorbents or organic solvents. While techniques fulfill their tasks, they reveal some important inconveniences. In the case of liquid-liquid extraction, the problem lies in consumption of considerable quantities of organic solvents, which is both environmentally unfavorable and increases the costs of the analytical procedure (storage and utilization costs of these solvents). In the case of techniques in which adsorbents are used, problems may arise when polar or high molecular mass compounds have to be analyzed, or when phenomena of incomplete desorption or artifacts formation (like decomposition of some sample components) may occur. Thus, a number of techniques with reduced solvent consumption (Liquid Phase Microextraction) or practically solventless techniques (e.g., absorption in liquid-like polymers) have been introduced over the past two decades. These techniques show many favorable characteristics; nevertheless, they also have their own limitations. In this paper, a review of the wide spectrum of sample preparation techniques with special attention paid to environment-friendly techniques is presented. The techniques are described from the point of view of analyte isolation mechanisms, and both theoretical and technical aspects are discussed.