# Solid-Phase Microextraction Techniques and Application in Food and Horticultural Crops
## 3 Flavors and Aromas (Volatile Organic Compounds) in Foods Using HS-SPME
### Volatile Organic Compounds and Wine Quality  
HS-SPME combined with GC-MS has been widely used to determine the presence and concentration of volatile organic compounds in wine [7; 37; 38]. Many of these compounds are important in assessing wine quality, so it is important to have effective and reliable analytical methods for determining the presence of these compounds. Compounds responsible for aroma and taste can be classified into the following groups: aliphatic alcohols, benzenoids, carboxylic acids, sesquiterpenoids, and terpenes. Recently, [PERSON] et al. used HS-SPME with GC-MS to determine the volatile organic compound profile in two white wines (Trebbiano d'Abruzzo and Pecorino) from Abruzzo, Italy [39]. In their work, they used a response surface methodology in order to optimize the sensitivity of their method. The parameters optimized were the type of fiber used (either PDMS, CW/DVB, or PDMS/CAR/DVB), fiber exposure time, temperature, and NaCl concentration. Two different compounds, typical of those present in the wine volatile organic profile (ethyl decanoate (non-polar) and 3-methyl-1-butanol (polar)), were used as analytes in order to simplify the optimization process. The PDMS/CAR/DVB SMPE fiber extracted the largest number (around 70) of volatile organic compounds. The optimization process showed that the use of 10% NaCl with an extraction temperature of 50 \({}^{\circ}\)C or 30% NaCl with an extraction temperature of 30 \({}^{\circ}\)C, both resulted in the maximum extraction of volatile components. However, fewer volatile esters were preferentially extracted with 10% NaCl at 50 \({}^{\circ}\)C while more volatile esters were preferentially extracted with 30% NaCl at 30 \({}^{\circ}\)C.  
[PERSON] et al. used HS-SMPE to investigate the effect of the volatile wine composition on the response factor measured for a given volatile organic compound [40]. In order to simplify the work, nine volatile compounds were tested (ethyl hexanoate, ethyl decanoate, geraniol, hexanol, linalool, 3-methyl-1-butanol, nerol, and 2-phenylethanol). A 85 \(\upmu\)m PA SMPE fiber was used for all analyses. Method optimization involved in  
Figure 5: Main volatile compounds extracted from _Mycriaria jaboticaba_ fruit.  
vestigating the sample volume, fiber exposure time, extraction temperature and NaCl concentration. There was an increase in the peak area when the sample was stirred at 1000 rpm from 1.4 times for ethyl decanoate to 3.1 for linalool. When 200 g/L of NaCl was used, an increase of 1.4 times for ethyl decanoate to 6.4 for linalool was observed. However, extraction under increasing temperatures, 25, 30 and 40 \({}^{\circ}\)C, did not significantly change the amount of volatile compounds extracted, so 25 \({}^{\circ}\)C was used in all subsequent measurements. Changing the sample volume from 25, to 30 and 40 mL did change the amount of terpen and alcohols adsorbed. A sample volume of 30 mL was chosen, as the amount of terpenids adsorbed did increase when the sample volume increased from 20 mL to 30 mL. It was observed that significantly increasing the concentration of a particular volatile organic compound resulted in a decrease in adsorption of the other volatile organic compounds present. In particular, compounds with high relative response factors were less affected by matrix effects in the sample.