Chemical warfare agents (CWAs) are a growing concern for many countries. The uses of CWAs as they can be synthesized by simple chemical reactions, and often have an extremely high toxicity. Conventional, analytical techniques for the detection of nerve agents from environmental and biological samples include gas chromatography, liquid chromatography, gas chromatography– mass spectrometry, ion chromatography, atomic emission detection, capillary electrophoresis, etc. These methods have very high sensitivity, reliability, and precision. However, in spite of these advantages, these techniques require expensive instrumentation and highly trained personnel. They also are time-consuming and unsuitable for field analysis. To meet these prerequisites of rapid warning and field deployment, more compact, low-cost instruments are highly desirable for facilitating the task of on-site monitoring of nerve agents. a quartz crystal microbalance (QCM) sensors could be a reliable and promising alternative to routine methods because of their simplicity, ease of use and high sensitivity and selectivity.1,2 In this study, we prepared QCM sensors functionalized with –NH2 and –COOH groups for differentiate diethyl ester phosphonic acid (DEHP) from diethyl phthalate (DEP), which are known as G and VX agent stimulants respectively. Infrared spectroscopy (FT-IR) was performed in order to characterize the surface of the sensor after modification and the detection. Furthermore, impact of hydrogen bonds on detection will be discussed.