Sample Preparation of Volatile Organic Compounds with Needle−Type Extraction Device

Quantification of volatile organic compounds (VOCs) in environmental air has been recently focused because of their adverse effects on human health, including the so−called multiple chemical sensitivity and sick building syndrome [1,2]. To investigate the effect of VOCs on human health and prevent the above illnesses, a sensitive and reliable method for determining the VOCs in air samples is desired. For the determination of gaseous VOCs, the analysis in gas chromatography (GC) is one of the most promising methods, because of its selectivity and sensitivity, as well as wide availability [3,4]. However, a sample preconcentration process should still be needed for an accurate and precise determination of these VOCs. Typically, two types of sample preparation methods have been employed for the concentration of VOCs in air samples, i.e., solvent desorption and thermal desorption (TD) methods. The solvent desorption method showed relatively low sensitivity, and the solvent peak can often interferes some analytes in the chromatogram. The TD is a solvent−free technique and has a high sensitivity, however, it requires a relatively expensive, specially−designed desorption instrument. Solid−phase microextraction (SPME) is one of the most advanced sampling techniques for typical VOCs analysis in GC, and it has several attractive features over other traditional sample preparation techniques [5]. However, most of the SPME techniques are based on static sampling, therefore, a relatively long extraction time is needed to obtain a satisfactory sensitivity. As an alternative to the active extraction of VOCs, the use of needle−type extraction Focusing Review