Characterisation of QMB sensors by means of the BET adsorption isotherm

A calibration protocol was established for a quartz microbalance-based electronic nose (QMBE-nose) that was used for apple aroma measurements. A gas-mixing panel was built to generate a broad concentration range of single apple volatile compounds and of mixtures of two compounds. The response of each QMB sensor was modelled with BET adsorption isotherms. Results show that the affinity of the different sensors to relative humidity can be described well with the BET parameters. The sensors could also be characterised with this model for affinity towards single apple volatiles and mixtures of two apple volatile compounds. By means of multivariate analysis on all sensor responses, the different compounds could be discriminated well and also quantified accurately. The results showed the potential of the QMBE-nose to quantify and discriminate different apple volatile compounds. Also, the established calibration protocol offers an easy and fast tool to characterise new sensors or investigate new application possibilities.