Smartphone-based Electrochemical Impedance Detecting System And Research For Volatile Organic Compounds

Electrochemical impedance measurement,as a common electrochemical sensing method,has many advantages such as high sensitivity,easy-to-operation and quick detecting speed.Therefore it is especially suitable for the integration of microarray and miniaturized devices.In this study,a smartphone-based electrochemical impedance sensing system was designed and developed.This system was composed with miniaturized sensor,portable detecting device and smartphone.The interdigital electrodes modified with zinc oxide(ZnO),graphene,and nitrocellulose were used as sensors to produce impedance responses to target analytes.Portable detecting device could transfer responses of electrodes to electrochemical signal by using certain electrochemical methods.The smartphone could control the hand-held device via one of communications like Bluetooth,tansfer data and report the concentration of target analytes on the interface.The smartphone-based system was demonstrated to detect VOCs at real time.The results proved that this system had impedance responses to VOCs but did not have specificity so,VOCs were further distinguished by using their sensitive frequency point.Especially,VOCs like acetone from human exhaled breath can serve as significant biomarkers of some diseases,such as diabetes.Therefore,those diseases could be non-invasive monitored through monitoring exhaled breath of human.Finally,measurements of the exhalations from human being were carried out to obtain the concentration of acetone in exhaled breath before and after intense exercise.The results proved that the smartphone-based system could be applied on the detection of VOCs in real settings for healthcare diagnosis.Thus,the smartphone-based electrochemical impedance sensing system provided a convenient and quick approach to detect VOCs in exhaled breath and possibly allowed for early diagnosis of some diseases.