Short time gas delivery pattern improves long-term sensor reproducibility

The long-term reproducibility of responses is one of the most demanded qualities of chemical sensors. Among the several phenomena affecting the reproducibility those related to imperfect experimental design are sometimes dominant. In this work an experimental design centered on a pattern of short-time repeated exposures (STE) to gases is presented as a method to increase the reproducibility of sensors responses. The method was validated in a experiment where an array of metalloporphyrins coated quartz microbalances is used to classify two volatile compounds and their mixture. The experiment was designed in order to compare the performance of the proposed method with that achieved with the standard long-time gas exposures. The STE results show an improvement of the reproducibility of the sensorial system respect to the standard protocol providing a complete identification after 45 days from the training procedure. The results also evidence the fundamental role of the first exposure to improve the reproducibility of the other pulses responses composing STE pattern.