Organophosphate sensing with vic-dioximes using QCM sensors

Vic-dioximes, a class of organic chemical compounds, are proposed for the first time as effective sensing materials for the detection and quantification of organophosphates with chemical gas sensors. The described vic-dioximes are derivatives of glyoxime and were substituted in 1,2 positions with alkylthiols of varying chain lengths. These oximes in the free form are powerful H bond donors that interact strongly but reversibly with H bond acceptors such as organophosphates leading to a high and selective enrichment of these molecules in the sensitive material. Using 10 MHz quartz crystal microbalance sensors an extraordinary high sensitivity (up to 260 Hz/ppm) to the test analyte dimethyl methylphosphonate (DMMP) and detection limits in the low parts-per-billion range were obtained. At the same time, the humidity influence and cross-interferences to common volatile organic compounds are low. The substituted vic-dioximes are obtainable via a simple synthesis route and thus readily available as sensing material for chemical sensors.