# Solid-Phase Microextraction Arrow for the Sampling of Volatile Organic Compounds in Milk Samples
## 4 Conclusions
After extraction, the VOCs were thermally  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Compound** & **Retention Time** & **Identification 1** & **Molecular Weight** & **Molecular Formula** & **Milk 1** & **Milk 2** & **Milk 3** \\ \hline Acetone & 4.8 & RL, MS, STD & 58 & C\({}_{3}\)H\({}_{50}\)O & 4.90 \(\pm\) 0.07 & 8.84 \(\pm\) 0.71 & 0.07 \(\pm\) 0.01 \\ \hline
2-Butanone & 6.5 & RL, MS & 72 & C\({}_{3}\)H\({}_{50}\)O & 17.62 \(\pm\) 1.11 & 34.00 \(\pm\) 1.56 & 32.41 \(\pm\) 5.71 \\ \hline
2-Pentanone & 9.4 & RL, MS & 86 & C\({}_{5}\)H\({}_{50}\)O & 3.23 \(\pm\) 0.41 & 4.86 \(\pm\) 0.42 & 2.83 \(\pm\) 0.34 \\ \hline
2-Heptane & 9.7 & RL, MS, STD & 100 & C\({}_{5}\)H\({}_{16}\) & 5.30 \(\pm\) 0.62 & 2.65 \(\pm\) 0.17 & 3.38 \(\pm\) 0.21 \\ \hline Methyl isobutyl & & & & & & \\ ketone (IS) & 11.3 & RL, MS, STD & 100 & C\({}_{6}\)H\({}_{12}\)O & - & - & - \\ \hline
4-Methyl-heptane & 11.6 & RL, MS & 114 & C\({}_{6}\)H\({}_{18}\) & 3.45 \(\pm\) 0.21 & 0.84 \(\pm\) 0.07 & 1.54 \(\pm\) 0.11 \\ \hline
3-Dimethyl-hexane & 11.8 & RL, MS & 114 & C\({}_{6}\)H\({}_{18}\) & 5.12 \(\pm\) 0.74 & 0.63 \(\pm\) 0.05 & 2.25 \(\pm\) 0.02 \\ \hline
5-Methyl-1-heptene & 12.0 & RL, MS & 112 & C\({}_{6}\)H\({}_{16}\) & 0.87 \(\pm\) 0.14 & ND\({}^{2}\) & 0.25 \(\pm\) 0.01 \\ \hline
4-Methyl-heptane & 12.3 & RL, MS & 114 & C\({}_{6}\)H\({}_{18}\) & 2.35 \(\pm\) 0.24 & 3.61 \(\pm\) 0.91 & 1.29 \(\pm\) 0.09 \\ \hline
1-Pentanol & 12.4 & RL, MS & 88 & C\({}_{5}\)H\({}_{12}\)O & 5.11 \(\pm\) 0.54 & 3.75 \(\pm\) 0.22 & 2.30 \(\pm\) 0.02 \\ \hline
2,2-5-Timethyl-hexane & 12.9 & RL, MS & 128 & C\({}_{5}\)H\({}_{13}\) & 1.18 \(\pm\) 0.10 & 0.34 \(\pm\) 0.02 & 0.78 \(\pm\) 0.03 \\ \hline
2-Ethyl-1-hexene & 13.2 & RL, MS & 112 & C\({}_{6}\)H\({}_{13}\) & 1.12 \(\pm\) 0.09 & 0.43 \(\pm\) 0.03 & 0.54 \(\pm\) 0.05 \\ \hline
4-Methyl-2-hexanone & 13.3 & RL, MS & 114 & C\({}_{7}\)H\({}_{14}\)O & 0.65 \(\pm\) 0.04 & 0.75 \(\pm\) 0.03 & ND \\ \hline Octane & 13.6 & RL, MS, STD & 114 & C\({}_{6}\)H\({}_{18}\) & 1.75 \(\pm\) 0.05 & 2.39 \(\pm\) 0.06 & 0.84 \(\pm\) 0.07 \\ \hline Hexanal & 13.7 & RL, MS & 100 & C\({}_{6}\)H\({}_{12}\)O & 3.76 \(\pm\) 0.10 & 1.15 \(\pm\) 0.01 & 2.44 \(\pm\) 0.15 \\ \hline
2-Octene & 14.2 & RL, MS & 112 & C\({}_{6}\)H\({}_{16}\) & ND & 0.10 \(\pm\) 0.01 & 0.13 \(\pm\) 0.01 \\ \hline
2,4-Dimethyl-1-heptene & 15.3 & RL, MS & 126 & C\({}_{6}\)H\({}_{18}\) & 9.46 \(\pm\) 0.59 & 7.48 \(\pm\) 0.65 & 6.09 \(\pm\) 0.39 \\ \hline
2-Heptanone & 17.2 & RL, MS & 114 & C\({}_{7}\)H\({}_{14}\)O & 57.00 \(\pm\) 2.0 & 56.78 \(\pm\) 5.81 & 34.62 \(\pm\) 3.65 \\ \hline Styrene & 17.3 & RL, MS & 104 & C\({}_{6}\)H\({}_{8}\) & 0.46 \(\pm\) 0.03 & 1.16 \(\pm\) 0.10 & 1.98 \(\pm\) 0.11 \\ \hline Heptanal & 17.7 & RL, MS & 114 & C\({}_{7}\)H\({}_{14}\)O & 2.04 \(\pm\) 0.02 & 10.67 \(\pm\) 0.98 & 0.87 \(\pm\) 0.07 \\ \hline
7-Octen-2-one & 18.8 & RL, MS & 126 & C\({}_{6}\)H\({}_{14}\)O & 1.17 \(\pm\) 0.01 & 0.74 \(\pm\) 0.06 & 1.86 \(\pm\) 0.08 \\ \hline a-Pinene & 19.0 & RL, MS & 136 & C\({}_{6}\)H\({}_{16}\) & 0.43 \(\pm\) 0.03 & 0.43 \(\pm\) 0.02 & 0.36 \(\pm\) 0.02 \\ \hline
4-Ethyl-2-octene & 19.2 & RL, MS & 140 & C\({}_{6}\)H\({}_{20}\) & 0.19 \(\pm\) 0.01 & 0.16 \(\pm\) 0.01 & 0.10 \(\pm\) 0.01 \\ \hline
3-Ethyl-2-methyl-1-heptene & 19.3 & RL, MS & 140 & C\({}_{6}\)H\({}_{20}\) & 0.27 \(\pm\) 0.02 & 0.21 \(\pm\) 0.01 & 0.14 \(\pm\) 0.01 \\ \hline
4-Methyl-nonane & 19.9 & RL, MS & 142 & C\({}_{6}\)H\({}_{12}\) & ND & 0.28 \(\pm\) 0.02 & 0.25 \(\pm\) 0.01 \\ \hline
2-Methyl-3-octanone & 20.6 & RL, MS & 142 & C\({}_{6}\)H\({}_{13}\)O & 0.81 \(\pm\) 0.01 & 0.72 \(\pm\) 0.04 & 0.89 \(\pm\) 0.07 \\ \hline
2-Ethyl-1-octene & 20.8 & RL, MS & 140 & C\({}_{6}\)H\({}_{20}\) & 7.65 \(\pm\) 0.64 & 0.28 \(\pm\) 0.02 & ND \\ \hline Decane & 21.2 & RL, MS, STD & 142 & C\({}_{6}\)H\({}_{22}\) & 4.45 \(\pm\) 0.38 & 1.77 \(\pm\) 0.09 & 2.20 \(\pm\) 0.17 \\ \hline
4-Methyl-decane & 21.6 & RL, MS & 156 & C\({}_{11}\)H\({}_{24}\) & 0.37 \(\pm\) 0.03 & 0.51 \(\pm\) 0.04 & 0.41 \(\pm\) 0.04 \\ \hline Heyl acetate & 21.7 & RL, MS & 144 & C\({}_{6}\)H\({}_{13}\)O\({}_{2}\) & 1.24 \(\pm\) 0.09 & ND & 0.99 \(\pm\) 0.08 \\ \hlinedesorbed in the modified GC injection port, followed by their determination in a GC-MS system.