(668e) Metal-Organic Frameworks As Food Spoilage Indicators

Food spoilage is associated with the release of Volatile Organic Compounds (VOCs), which usually accumulate into the food package headspace and provide useful information about the quality of the food product itself. Smart packages that integrate miniaturized optical sensors targeted towards food spoilage indicators may be used to monitor the products quality in real-time. Affinity layers represent a core component ofchemical sensors for the selective and sensitive detection of analytes. In this work, Metal-Organic Frameworks (MOFs) were evaluated as affinity layer for food spoilage indicator applications. A novel innovative experimental methodologywas developed to determine the enrichment of individual spoilage indicators from a mixture at ppm level in the nanopores of the MOFs.

Multicomponent breakthrough curves of a mixtureof ethanol, ethyl acetate, 2-butanone and 2,3-butanedione)were measured on two highly stable MOFs, namely ZIF-8 and UiO-66, using Selected Ions Flow Tube Mass Spectrometry (SIFT-MS) for monitoring. Both MOFs share preferentiality towards the adsorption of hydrophobic molecules. Very large enrichment factors (between 100 and 5000) show that these materials can increase many-fold the adsorbed phase over gas phase concentration, even when present at ppm levels, which is crucial for the good operation of affinity layer based sensors. Furthermore,VOCs adsorption on UiO-66 unveils intricate competitive mechanisms, leading to multiple steps of ethanol displacement while simultaneous adsorption of ethyl acetate, 2-butanon and 2,3-butanedione occurs.