Thermal desorption based enrichment is a general concept that can enhance any detection system's sensitivity and selectivity. Given their large interior surface area and chemical versatility, archetype metal–organic frameworks (MOFs) are selected for preconcentration of explosives and their precursors occurring in low concentrations, and are compared to the state‐of‐the‐art sorbent Tenax TA. Applying inverse gas chromatography (iGC), this study shows that several archetype MOFs, namely HKUST‐1 and MIL‐53, surpass Tenax regarding their specific retention volume for nitromethane, a typical ingredient in improvised explosives. Using linear hydrocarbons as reference probe molecules, the dispersive surface energy is determined for all MOFs along with the specific contribution of the nitro group for HKUST‐1 and ZIF‐8. Trends from pulse‐chromatographic iGC‐investigations are mostly followed in breakthrough and thermal desorption experiments using a 1000 ppm nitromethane source. In these experiments, HKUST‐1 proves the peak substance, with enrichment factors being 109‐fold higher than for Tenax, followed by MIL‐53. In case of HKUST‐1, this factor is successfully reproduced for a 1 ppm concentration scenario. This shows that archetype MOFs can be suitable or even superior candidates for a sensitive sensing of nitroalkane explosives from the gas phase by a concept of preconcentration.
Ever since the days of the Garden of Eden mankind has been interested more or less in fabrics of either animal or vegetable origin. We are still copying, in a way, the procedure of that day, only using mulberry leaves, and at present are fashioning our fabrics from the stalk fibers and even from the wood itself. The most important textile fibers at the present time are linen, wool, cotton, silk, and rayon. Some of the very oldest fabrics which are in existence come from the tombs of Egypt. These were undoubtedly the clothing of those early JOURNAL OF CHEMICAL EDUCATION
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