## 1 Introduction
In the fields of the various applications, including environmental pollutant monitoring, discrimination of botanical and geographical origin for organisms, detection of off-flavors in raw materials of food, diagnostic of a disease through breath emitted from patients, tracking out drugs and explosives, and the measurements of the change of aroma quality according to real-time for living-organisms, there is an enormous demand for sensors which have a wide working range to detect volatile organic compounds. Finally, the SAW detector in zNose is a small miniature vapor chemical sensor used to detect volatile organic compounds in a wide range. The base material of a SAW device is an uncoated piezo-electric quartz crystal. This crystal is in contact with a thermoelectric element, which controls the temperature for cooling during vapor adsorption and for heating during desorption. The crystal operates by maintaining highly focused and resonant surface acoustic waves of 500 MHz on its surface. When an analyte adsorbs on the surface of the sensor, the frequency of the surface acoustic wave is altered, which in turn affects the detection signal and allows identification of the compounds. Especially, the characteristic of simplicity of fast GC/SAW method does not demand extraction procedures and provides on-line measurements. The headspace vapor of sample is swept into the inlet via a pump, and then the vapor passes through the valve where the compounds are adsorbed onto the trap inside the system. Switching the valve to the injection process causes helium gas to flow backwards through the trap and onto the column [22, 25]. Therefore, GC/SAW has diminished decomposition of plant materials, and minimized activity of enzyme. Especially, fast GC/SAW permits a high reproducibility and good sensitivity at the high picogram to nanogram level, making it possible to detect sensitive living volatile materials quantitatively [22]. Also, GC/SAW allows pattern recognition by a visual fragrance pattern, called a VaporPrint or chromatographic fingerprint derived from the frequency of a SAW sensor [20, 21, 22, 23, 24, 25]. Chromatographic fingerprint technique has been internationally accepted as a useful means for quality control [28, 29]. Therefore, fast GC/SAW method allows to monitor rapid change in volatile emission, and this method can be used in the field facilitating reliable ecological studies on living organism under undisturbed conditions in real time. The advantages and the method validation of GC/SAW, adaptability to a variety of applications were reported in my previous publications [20, 21, 22, 23, 24, 25]. Some papers were published about the analysis of chemical compositions of essential oil for _H. cordata_ Thunb which are originated from China by GC-MS [29, 30]. Also, the paper reported on the analysis of volatiles of _H. cordata_ Thunb which are from China by HS-SPME-GC-MS [31]. However, no paper has reported on the analysis of volatile compounds of _H. cordata_ Thunb which are from South Korea by using fast GC/SAW and HS-SPME-GC-MS. The aim of this study is to show a novel quality control by fast GC/SAW methodology for the discrimination of the three different parts of the plant such as leaves, aerial stems, and underground stems for _H. cordata_ Thunb which are from South Korea. In addition, volatile composition profile data for _H. cordata_ Thunb by GC/SAW were analyzed by PCA. Also, HS-SPME-GC-MS method was employed to confirm the identification of volatile compounds of _H. cordata_ Thunb and compared to GC/SAW.