Developing a mass sensitive sensor for determination of amine vapors

The purpose of this work is to develop a sensor to determine amine vapors. For this intend, we used commercial ULTEM polymer, and modified it with 3,4-diaminobenzhydrazide. The –NH2 substances of the concluding molecule have bonded with glutaraldehyde and, thus it became sensitive to amine vapors. This polymer has been coated onto a quartz crystal electrode and with quartz crystal microbalance oscillator it is developed to be a mass-sensitive sensor. After the process, even though the modification grade of the obtained polymer is not relatively high, it can be observed that the polymer is sensitive to ammonia and amine vapors, and can give reproducible responses. We gathered linear and logarithmic correlations between the frequence shifts and the addition of amine compounds. Furthermore, this sensor gave linear and reproducible responses to the relative humidity in a wide range. This sensor gave weak responses to aliphatic hydrocarbons, on the other hand, it gave relatively strong responses to ethanol and acetone vapors. However, it has been seen that the hydrophilic property of the polymer has advanced. For examining the modification of ULTEM polymer, the experiments were repeated with an unmodified ULTEM polymer coated QCM electrode. After these experiments, even the pure ULTEM polymer coated electrode is good for relative humidity measurements, it is not suitable for amine vapors because of its unreproducible responses. For the conclusion of this experiment, it is shown that this sensor can be used for determining the amine vapors that is formed from the bacterial decomposition and so freshness testing, and relative humidity measurements.