Sample-extraction methods for ion-mobility spectrometry in water analysis

The requirement to monitor the chemical quality of water has become one of the major issues in environmental analytics. Ion-mobility spectrometry (IMS), a fast, sensitive method traditionally used in security and military applications, is also suitable for environmental analysis and detection of organic pollutants from aqueous matrices, when combined with advantageous methods to isolate analytes from the water phase. This article reviews the current literature on the sample-extraction methods most feasible for aqueous samples prior to ion-mobility analysis, and highlights their principles and trends in IMS applications. These partition-based methods include solid-phase microextraction, stir-bar sorptive extraction, single-drop microextraction, hollow-fiber liquid-phase microextraction, pervaporation-membrane extraction and paper spray. We also discuss comparisons of method characteristics and relative performance, and conclude that IMS is a potential method for both on-line and on-site determination of organic pollutants in aqueous matrices.