High-performance fixed-bed in situ mass analyzer—ISMA

Abstract

We demonstrate a newly developed high-performance fixed-bed reactor combined with an in situ mass analyzer (ISMA). The ISMA is particularly relevant to sub-second time-resolved studies where mass changes occur due to, e.g., chemical reactions and process conditions such as choice of solid, temperature, gas atmosphere, and pressure. The mass is determined from the optically measured oscillation frequency of a quartz element, yielding a mass resolution below 10 μg—typically 2–3 μg—for samples up to ∼500 mg. By placing the quartz element and optical sensor inside stainless steel pipes and providing heat from the outside, the instrument is applicable up to ∼62 bars and 700 °C. By surrounding this core part of the instrument with a suitable feed system and product analysis instruments, in combination with computer control and logging, time-resolved studies are enabled. The instrument with surrounding feed and product analysis infrastructure is fully automated. Emphasis has been put on making the instrument robust, safe, operationally simple, and user-friendly. We demonstrate the ISMA instrument on selected samples.