Abstract
Degradation is inherent part of odour sampling and olfactometery analysis. There are many techniques that can be deployed in order to minimize sample degradation, such as nitrogen-based pre-dilution and sealed transportation vessels. Despite the best efforts to keep the volatilization at bay - sample degradation has forced European and American standards to implement a thirty (30) hour expiration on all odour samples. German standard VDI3880, and possible the soon to be revised EN13725 standard, limit sample storage to 6 hours unless it can be shown that the sample degradation is within acceptable limit. On-site olfactometers such the Scentroid SM100, can be used, and are widely used in Canada, as part of the quality assurance program by measuring samples immediately after acquisition and immediately prior to analysis by the laboratory to ensure odour degradation is within these defined limits. However, observations have shown samples can degrade by an order of ten magnitudes in a span of less than 24 hours. This study provides data on sample degradation from a variety of sources over a span of 24 hours. Samples will be stored in Nalophan, Tedlar®, and the newly introduced PTFE bags. Data has shown that the much higher density of PTFE provides slower sample degradation than Tedlar® or Nalophan. This is especially true of samples with high humidity, Ammonia, or H2S. To properly simulate shipping conditions a portion of the study focuses on samples that are subjected to lower pressure and temperature similar to those found in standard cargo planes. These samples are compared to those which have been stored at standard conditions (room temperature at 1 atmosphere). Further study has been made on degradation of sample with highly volatile compounds such as ozone.
