Sampling and preconcentration techniques for determination of volatile organic compounds in air samples

Because air is complex and heterogeneous, continuously evolving in time and space and being influenced by atmospheric and geographical conditions, sampling is crucial in air analysis. Moreover, due to the low levels of pollutants present in the atmosphere, enrichment is often required.This review deals with the most common techniques for sampling and preconcentration of volatile organic compounds (VOCs) in air samples (e.g., whole-air collection in containers, which is usually combined with preconcentration step, and solid-sorbent enrichment methods). We also describe solid sorbents used to trap VOCs in air, and subsequent desorption techniques.In recent years, there have been many efforts to improve on-line analysis methods, which offer real-time data and are useful in providing rapid results. We examine the application of sorbent trapping to on-line analysis and other techniques for on-line analysis (e.g., membrane extraction and selected-ion-flow-tube mass spectrometry).