Iron sensors for domestic applications

Garcia, Yann [UCL]

In recent years, attention has been focused on the efficient detection of chemical pollutants, especially small volatile organic compounds (VOCs) and hazardous gases (HGs).1 VOCs can easily enter the body through breathing, and cause serious health issues.2 Our investigations led us to focus on a series of mononuclear azole based complexes,2-6 as well as on spin crossover capsules.7,8 For instance, [Fe(H2btm)2(H2O)2]Cl (1) (H2btm = di(1H-tetrazol-5-yl)methane), which can detect at real time, with a high selectivity and ultra-sensitivity, 14 VOCs and HGs.2 In particular amines, which are detected quickly (< 2 min). The detection is accompanied by significant and fast colour changes detectable by the naked-eye at ambient conditions or by a smartphone-based colorimetric method.2 After VOCs adsorption, a spin state occurs, which was probed by 57Fe Mössbauer spectroscopy. In addition to its high thermal stability (up to 170 °C), 1 showed excellent reusability by consecutive seven cycles of adsorption–desorption. This sensor is low-cost, environmentally friendly, easy to use, and shows fast detection performances. Such features offer attractive prospects for 1 which could be used for in-field detection and food safety control in environmental conditions, e.g. for meat freshness control.6 In this lecture, I will review latest advances highlighting the impact of our new sensors for quantitative analysis of spin states of selected iron(II) complexes, used as sensors for various toxic industrial chemicals (TICs).