## Results and Discussion
### Volatile Compounds of Portuguese Honeys
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline  & \multirow{2}{*}{**RT**} & \multirow{2}{*}{**Compounds (ug/kg)**} & \multirow{2}{*}{**RI\({}_{\text{avg}}\)**} & \multirow{2}{*}{**RI\({}_{\text{fit}}\)**} & \multicolumn{4}{c}{**Beachyptus**} & \multicolumn{4}{c}{**Chestunt**} & \multicolumn{2}{c}{**Heather**} \\ \cline{4-11}
**RT** & & & & & & & & & & & & \\ \hline
28.78 & 1,3.5-tris(1-methylylethyl)-benzene & 1622 & - & ni & ni & ni & ni & ni & ni \\ \hline
28.90 & Recycl(5.3.0)dequemente (Axulene) & 1620 & - & 97 & 30.70 \({}^{\text{maxmax}}\) & 10.83 & ni & ni \({}^{\text{maxmax}}\) & ni & ni & ni \\ \hline
29.78 & Hepadecane & 1679 & 1700 & 98 & 159.80 \({}^{\text{maxmax}}\) & 75.10 & ni & ni \({}^{\text{maxmax}}\) & ni & 97 & 197.13 & 14.44 \\ \hline
32.81 & Eicosane & 1876 & 2000 & ni & ni \({}^{\text{maxmax}}\) & ni & ni & ni \({}^{\text{maxmax}}\) & ni & 98 & 243.75 \({}^{\text{maxmax}}\) & 5.40 \\ \hline
34.48 & Hexadecane acid ethyl ester & 1966 & 1975 & ni & ni \({}^{\text{maxmax}}\) & ni & 97 & 31.91 \({}^{\text{maxmax}}\) & 2.60 & ni & ni \({}^{\text{maxmax}}\) & ni \\ \hline Sum of Volatiles (ug/kg) & & & & & & & & & & & \\ \hline \hline RT; retention time, RI\({}_{\text{avg}}\); experimental retention indices values based on the calculations using the standard mixture of alkanes. RI\({}_{\text{fit}}\); Retention indices of the identified compounds according to literature data edited in Wiley 7 NIST MS library. Qualification: Percentage accuracy of volatile compounds identified using Wiley 7 NIST MS data Different letters (superscripts) in each row indicate statistically significant differences at the confidence level \(p<0.05\). Superscripts have been inserted according to the hierarchy in lettering of the alphabet. ni: not identified, were treated as zeros for statistical analysis. Results reported are the average \(\pm\) standard deviations values of two independent replicates (\(n\) = 2). & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: _Cont._[PERSON] et al. [44] using solid phase microextraction followed by gas chromatography coupled to mass spectrometry reported the presence of 35 volatile compounds in Spanish eucalyptus honeys. Volatiles such as isoborneol (or borneol), nonanal, benzaldehyde, benzeneacetaldehyde (or phenylacetaldehyde), 4-oxoisophorone (or 4-ketoisophorone) were identified in considerable amounts (ug/kg), in agreement with present results involving Portuguese eucalyptus honeys. [PERSON] et al. [45] using headspace solid phase microextraction coupled to gas chromatography quadrupole mass spectrometry reported the presence of 110 volatile compounds in wildflower,  
Figure 3: A typical gas chromatogram of heather honey from the region of Coimbra, Vila Nova de Ceira, in Portugal. 20: Heptane. 21: Benzeneacetaldehyde. 22: cis-Linalool oxide. 23: Hotrienol. 24: alpha-Isophorone 25: 1,2-dihydro-1,1,6-trimethyl-Naphthalene. 26: Eicosane. IS: Internal standard. Figure 2: A typical gas chromatogram of chestnut honey from the region of Braganca, Vinhais, in Portugal. 9: 2-methyl-2-Butenal. 10: 3-methyl-butanoic acid ethyl ester. 11: Benzaldehyde. 12: 2-hydroxy-Benzaldehyde. 13: Nonanal. 14: 1-Nonanol. 15: Benzoic acid ethyl. 16: Nonanoic acid ethyl ester. 17: 2,6-bis-(1,1-trimethyl)-2,5-cyclohexadiene-1,4-dione. 18: Dodecanoic acid ethyl ester. 19: Hexadecanoic acid ethyl ester. IS: Internal standard. eucalyptus, hissed and rosemary honeys from four different regions of Madeira Island. Among the aforementioned volatile compounds, linalool, trans-linalool oxide, 4-ketoisophorone, benzaldehyde, benzeneacetaldehyde, decanal, naphthalene and so forth, were identified in Eucalyptus spp. honeys, in conformity with present results. [PERSON] et al. (2014) using solid phase microextraction coupled to gas chromatography mass spectrometry reported that 53 volatile compounds dominated the headspace aroma of Greek chestnut honeys. Numerous of the aforementioned compounds were also identified in Portuguese honeys of the present work.