Modern methods of sample preparation for GC analysis

Today, a wide variety of techniques is available for the preparation of (semi-) solid, liquid and gaseous samples, prior to their instrumental analysis by means of capillary gas chromatography (GC) or, increasingly, comprehensive two-dimensional GC (GC × GC). In the past two decades, a large number of 'modern' sample-preparation techniques has been introduced, which have partly superseded their 'classical' counterparts. These novel techniques include off-line and on-line (sometimes semi- or fully automated) procedures, and exhaustive extraction as well as equilibrium techniques. In order to improve overall performance, aspects such as essentially organic solvent-less approaches, large-volume injection and miniaturization receive increasing attention. In most recent applications, mass spectrometric or element-selective detection have been used. The present review discusses the advantages and disadvantages, and relative performance, of most of the modern sample-preparation techniques and cites a number of illustrative applications for each of them.