An online detection system for the assessment of VOC surface emissions

Online detection of volatile organic compounds is still a difficult topic, many tradeoffs have to be accepted regarding the selectivity, sensitivity and the suitability to analyze complex mixtures of volatile organic compounds (VOC), especially when portable systems are required. To analyze the emission of VOC from freshly produced surfaces an emission test cell with online detector was developed. The system consists of a mobile air supply unit to provide mass-flow-controlled, humidified inlet air, a surface test cell with laminar flow over the surface and a detector unit. To achieve a selective detection of a wide range of volatile organic compounds, a miniaturized ion mobility spectrometer with a multi-capillary column was utilized as online detector. Selected compounds could be measured with detection limits down to 10 mu g/m(3), but the limited resolution qualifies the system more for applications like production control, where VOC concentrations above 300 - 500 mu g/m(3) are to be expected.