ABSTRACT
In the field of Indoor Air Quality research, the measurement of volatile organic compounds (VOCs) demands instruments that are rapid, mobile, robust, highly sensitive and allow for simultaneous monitoring of multiple compounds. These instruments should also compensate for possible interferences from permanent gases and air humidity. Proton-transfer-reaction-mass-spectrometry (PTR-MS) has proved to be a valuable and promising technique that fits the mentioned requirements for a suitable online measuring device. In this study, five exemplary applications of PTR-MS are described: (i) release of paint additives during drying process, (ii) emission of VOCs from active hardcopy devices, (iii) reference material evaluation, (iv) diffusion studies, and (v) emission testing of building products. The examples are selected to illustrate possibilities and limitations of the PTR technique in this field of research. The quadruple-based PTR-QMS was able to determine the emission characteristics during the experiments, especially in case of depleting emission sources (e.g., reference material). This allows for chemometrical analysis of the measured release patterns and detection of underlying processes. However, PTR-QMS reaches a functional limit in case of compound identification. If identification of VOCs is necessary, the measurements need to be accompanied by GC/MS analytics or a PTR instrument with higher mass-resolution (e.g., PTR-TOF-MS).
Subject(s)
Air Pollution, Indoor/analysis , Volatile Organic Compounds/analysis , Construction Materials , Mass Spectrometry , PaintABSTRACT
The principal digestive anomalies detected by radiological examination in dermatomyositis are the motor and functional consequences of the smooth and striated muscle lesions in these tissues. Vascular changes cause ulcerations, located in any part of the digestive tract, but more frequently in the esophagus, duodenum, and small intestine. These ulcerations sometimes develop into pseudodiverticulae.
