Sample Preparation for Gas Chromatography

The success of a gas chromatographic analysis mostly depends on the sample preparation procedure. Biological and environmental samples are not suitable for direct analysis. Organic analytes can be separated from matrixes by extraction methods such as gas–solid, liquid–liquid, solid–liquid, purge-and-trap, headspace, solid-phase (SPE), solid-phase micro- (SPME), stir bar sorptive (SBSE), membrane assisted (MAE), supercritical fluid (SFE), and Soxhlet extractions. These extraction methods are called phase separation methods. Matrix solid-phase dispersion (MSPD) is a special highly efficient phase separation procedure for biological matrixes such as meat, liver, muscle, and vegetables. QuEChERS is a widely used standardized procedure for the sample preparation of fruits and vegetables for the determination of pesticide content. The aim of the extraction procedure is not only separation of organic analytes from matrixes but also concentration in another phase. If the organic analytes contain protic (active) hydrogen (alcohols, carboxylic acids, amines, oxo compounds, etc.) some derivatization reactions, such as acylation, alkylation, and silylation, might be needed. The aim of the derivatization is to increase the sensitivity of detection and thermal stability of the organic analytes. The other aspect of derivatization is to reduce the polarity of the compounds.