Detection of pollutant mixtures with mass sensitive sensor

In the era of technology the loading of the environment became a most actual topic and it is lower chemical emissions wherever possible. Therefore the surveillance of organic analyses in the gas phase is an essential requirement to protect the environment and people, following risen interest in work place monitoring. The aim of this work was to detect mixtures of analyses such as aromatic or halogenated hydrocarbons in the gas phase. For this purpose the most universal applicable mass sensitive Quartz-Micro-Balances (QMB) operating at 10 MHz were coated with supramolecular materials, such as β-cyclodextrines and calixresorcin-arenes. Combining several QMB devices to sensor arrays and making use of the methods of pattern recognition, such as partial-least-squares or artificial-neural-networks, makes the simultaneous detection of analyses in mixtures possible . Besides, mixtures, whose analyses show considerable differences in their physical properties, those with very small differences should be detectable. As an example for the latter mixtures of the xylene isomers were examined, because they differ only slightly in shape and show approximately no differences in their physical properties. In any case the organic analyses could be detected with an accuracy of about one percent and the water cross sensitivity of the sensor materials could be nearly eliminated by the use of pattern recognition techniques. In an application of chemical technology the course of a process should be monitored. As an example the formation of a Grignard compound was surveilled using a temperature controlled QMB device. It was possible to follow the reaction via the concentrations of the reactants in the gas phase and the end point of the reaction could be detected with an accuracy of about one percent. Thus mass sensitive devices coated with supramolecular sensor materials can be used to regulate automated dosage systems in chemical processes to prevent unnecessary loading of the environment. (author)