The use of microwave energy as a heating source for the field-based headspace sampling and the subsequent determination of various volatile organic compounds (VOCs) using a field-portable HAPSITE gas chromatograph-mass spectrometer has been evaluated. A significant advantage in time reduction has been observed when using microwave energy when compared to conventional resistive-based heating. Such time savings are critical in field operations involving equipment such as the HAPSITE where non-routine sampling is commonly performed and very quick turnaround time is usually needed. Further, the technology also showed significant improvements in terms of sensitivity, thus suggesting its applicability to a broader range of compounds and detection levels than cur-rent technologies. Crown Copyright (c) 2007 Published by Elsevier B.V. All rights reserved.