## 2 Results and Discussion
### Comparison of GC/SAW and HS-SPME-GC-MS method for H. cordata Thunb  
The compositions of the pharmacologically active volatile compounds of _H. cordata_ Thunb which are from Anmyeon Island, South Korea extracted by HS-SPME using CAR/DVB/PDMS fiber and then analyzed by GC-MS are presented in Table 1. Its GC-MS total ion chromatogram is shown in Figure 1B. The alphabetic numbers of the peaks shown in Figure 1B correspond to the numbers indicated in the GC/SAW chromatograms (Figure 1A). Fifty-five compounds were detected by HS-SPME-GC-MS. Major compounds were identified by a comparison of the retention times and mass spectra of authentic standards. Minor compounds were tentatively identified by matching with their mass spectra of Wiley/NIST Library in GC-MS software. HS-SPME-GC-MS have been used widely for the analysis of volatiles as high resolution capacity and wide linear dynamic range. Also it was reported that the calculated limit of detection (LOD) varied from 0.1-100 ng [34]. In my previous paper, Multi-point calibration was performed for the three representative characteristic components of _S. vulgaris variginata_ by GC/SAW. The calibration curves of the analytes showed good linearity over the range of 5.72-175 ng for benzyl methyl ether, 5.04-300 ngfor phenylacetaldehyde, and 49.4\(\sim\)1235 ng for \(\alpha\)-pinene. The obtained LODs, calculated at S/N = 3, varied from 500 pg (phenylacetaldehyde) to 13 ng (\(\alpha\)-pinene) (Table 2) [22]. In this study, the HS-SPME-GC-MS can detect 55 compounds in the _H. cordata_ Thunb which are from Anmyeon Island, South Korea, far more than what the GC-SAW could detect (16 compounds). The difference of trapping time used in these two methods in order to set the proper conditions leads to these results. The headspace vapor of sample was swept into the trap inside the system at 25 \({}^{\circ}\)C for 1 s by GC/SAW, whereas the SPME fiber was exposed to the headspace above the sample vial at 25 \({}^{\circ}\)C for 1 h by HS-SPME-GC-MS.  
As shown in Table 1, \(\beta\)-myrrene, _cis_-ocimene and decanal, which comprise 71.2% of the total amounts, are the dominant volatile components of leaves of _H. cordata_ Thunb, just as GC/SAW (71.0%). 2-Undecanone and lauraldehyde, as the characteristic components in _H. cordata_ Thunb, also comprised 0.7% and 4.4% of the total amounts, respectively. In aerial stems for _H. cordata_ Thunb, \(\beta\)-myrrene, _cis_-ocimene and decanal, which comprise 56.1% of the total amounts, are also the dominant volatile components. 2-Undecanone (0.7%) and lauraldehyde (0.4%) were found at low concentrations. The concentration of bornyl acetate (9.3%) is considerably higher than that of leaves (0.2%) and geranyl acetate (1.6%) was found, as GC/SAW. The total amounts of pharmacologically active volatiles of aerial stems for _H. cordata_ Thunb are lower 1.5 times than those of leaves. In underground stems for _H. cordata_ Thunb, monoterenes involving \(\beta\)-myrrene, _cis_-ocimene, \(\alpha\)-thujene, \(\alpha\)-pinene, camphene, sabinene, \(\beta\)-pinene, \(\alpha\)-terpinene, limonene, _trans_-ocimene, \(\gamma\)-terpinene, \(\alpha\)-terpinolene,5-methyl-3-(1-methyl-ethenyl)cyclohexene,1-methyl-3-(1-methylphenyl)cyclohexene which comprise 77.9% of the total amounts, are also the dominant volatile components. While the level of decanal (0.1%) was substantially lower than that of leaves (26.8%), such as GC/SAW. Also, the quantity of limonene (9.4%) is remarkably increased than that of leaves (0.1%), the concentration of bornyl acetate (7.2%) is considerably higher than that of leaves (0.2%) and geranyl acetate (1.1%) was found, as GC/SAW. 2-Undecanone (2.3%) and lauraldehyde (0.1%) were found a little, as shown in Table 1.  
As these results show, the dominant components and analytical tendency for _H. cordata_ Thunb detected by GC/SAW and HS-SPME-GC-MS are similar, but there is a difference of abundance ratios owing to the difference of extraction efficiency and response factor between these two methods.