# Optimization of HS-SPME-GC-MS for the Determination of Volatile Flavor Compounds in Ningxiang Park
## 3 Results and Discussion
### Influencing Factors on GC-MS Analysis
#### 3.1.5 Effect of Extraction Conditions on VFCs  
The temperature of the extraction process has an impact on both the extraction rate and extraction time. The extraction head will more quickly attain adsorption equilibrium if the extraction temperature parameters are identified under which the extraction head  
Figure 2: (**a**) The number of volatile flavor compounds detected under different equilibration time conditions; (**b**) the total amount of volatile flavor compounds detected under different equilibrium time conditions; (**c**) the number of volatile flavor compounds detected under different equilibrium temperature conditions; (**d**) the total amount of volatile flavor compounds detected under different equilibrium temperature conditions.  
more quickly absorbs volatile substances. Early in the extraction process, volatile chemicals are rapidly concentrated on the extraction coating, and as extraction proceeds, the rate of adsorption decreases. The adsorption of the extraction head is saturated as the equilibrium state approaches, and even increasing the extraction time has a small impact. Therefore, it is necessary to identify the best extraction conditions to improve the experimental efficiency.  
First, Figures S6 and S7 show that the separation effect between two compounds steadily improves with an increase in extraction time and temperature. The retention time (R.time) after 30 min of substance quantity and total amount significantly increased (\(p<0.05\)), as did the quantity and total amount of substances. When the extraction duration is short or the extraction temperature is low, the extraction effect is weak, resulting in poor GC-MS analysis findings due to the coating of the Gray50/30 extraction head. Second, both the total amount of substances and the number of substances that were detected significantly changed when the extraction conditions were altered (Figure 3a-d). The total amount of substances increased as the extraction time and temperature were increased, and at 100 \({}^{\circ}\)C, it reached its highest level (Figure 3d) and did not reach dynamic equilibrium. According to studies, there is a significant correlation among sample size, container volume, and test findings. In addition to improving repeatability, the detection threshold will rise as the sample size increases. The extraction time and temperature are no longer increased due to the effectiveness and simplicity of the test. Lower extraction temperatures result in more alkanes (Figure 3b) but lower total ion peak areas (Figure S7A,B), which means lower relative content. The relative content did not significantly vary as the extraction conditions changed (Figure 3c,d), suggesting that the newly discovered compounds included fewer alkanes. As the extraction temperature and duration increased, the number and total amount of detected unidentified compounds increased (Figure 3b,c).  
Figure 3: (**a**) The number of volatile flavor compounds detected under different extraction time conditions; (**b**) the total amount of volatile flavor compounds detected under different extraction time conditions; (**c**) the number of volatile flavor compounds detected under different extraction temperature conditions; (**d**) the total amount of volatile flavor compounds detected under different extraction temperature conditions.  
Therefore, altering the extraction conditions has a direct impact on the GC-MS analysis results, and the quantity and total amount of compounds discovered are positively connected with the temperature and duration of the extraction. To further examine the distinctions between Ningxiang pork and other varieties of pigs and to identify the distinctive flavor components of Ningxiang pork, it is advantageous to alter the adsorption impact of the extraction head on unknown compounds.