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Electronic sensor system for the characterisation of packaging emissions


As the ease of use of a new system is very much depending on the user interface extra software was devised to fulfil the needs of the EQCS application. With reducing the input information to the basic requirements a simple front end was provided that is freed from any ballast. This is also important with respect to a future implementation onboard a micro controller. This goes also in line with the cost efficient sampling system described in A. The software isn't only logging the data but also performs an evaluation on the basis of stored calibration data.
AppliedSensor developed a new sensitive layer for their silicone µ-MOS sensors. This special layer has the advantage that it shows reduced cross sensitivity to inorganic analytes as hydrogen and nitrogen dioxide. This property enables the sensor to detect hydrocarbons on a background of inorganic gases, which are common in environment. Combined with a very short response time, measurements with high resolution can be achieved. In addition the sensor has a low power consumption, which offers the use in mobile applications (battery operated). Besides this it's possible to glue the chip (sensor) directly on a PCB and omit expensive costs for packaging on a header. On basis of these sensors a new air classification module for indoor applications was developed
The combination of the new dedicated sampling system together with the driving electronics for the sensors and the software forms a new analytical device. This new device offers an easy to use and cost efficient method to carry out headspace analysis on various materials and especially on gravure printing samples. The system is designed to be placed at line and to be run by less skilled workers. It shouldn't be seen as complete replacement of classic analytical methods but as an additional screening tool that helps to discover deviations in the production at an early stage.
A new headspace sampling system was devised which is very cost efficient compared to the state-of-the-art systems. This is achieved by a method that omits many special and thereby expensive parts. It is built up modular and is easy adapted to specific sampling conditions if needed. The simple design includes a minimized fouling of analytes within the system. For the same reason the sample incubation is done in glass vials (recycling possible) with PTFE coated silicone septa. The System needs for operation electrical power and purified compressed air, which is carrier gas at the same time.
Analytical know-how on packaging materials: Having both classical recognized analytics like HS-GC/MS and a sensor system in parallel led to better understanding of the analytical methods for the latter technique in respect to printing materials. It was showing that a separation of organic solvents and water is necessary in order to have comparable results as a certain cross sensitivity with water is still given for the sensors. And in case of printing materials water isn't a minor component. Finally, the separation is managed by a packed column with a special phase in isothermal mode. But already with direct methods different printing techniques can be differentiated as shown in a early project stage.