## 2 Materials and Methods
### GC-MS Conditions  
All analyses were conducted on a 7890A/5975C Triple-Axis Detector diffusion pump-based GC-MS (Agilent, Wilmington, DE, USA) equipped with a split/splitless inlet and MPS2 (Gerstel, Mulheim an der Ruhr, Germany) autosampler capable of automated SPME. The inlet was equipped with a 0.75 mm ID SPME liner (Supelco, Bellefonte, PA, USA) and operated in splitless mode. For separation, a 60 m \(\times\) 0.25 mm DB-WAXetr (Agilent, Santa Clara, CA, USA) column with a film thickness of 0.50 \(\upmu\)m was used at the constant flow of He (1.0 mL min\({}^{-1}\)). Owen temperature was programmed from initial 35 \({}^{\circ}\)C (held for 5 min) to 150 \({}^{\circ}\)C (held for 5 min) at the heating rate of 10 \({}^{\circ}\)C min\({}^{-1}\), then to 250 \({}^{\circ}\)C (held for 7 min) at the heating rate of 10 \({}^{\circ}\)C min\({}^{-1}\). Total GC run time of the analysis was 38.5 min. The MS detector worked in selected ion monitoring (SIM) mode. All ions were divided into six consequently detected groups for better shape of peaks and lower limits of detection (Table 2). An example of a chromatogram is shown in Figure S1 in Supplementary Materials. Peaks were identified using retention times of each analyte, which were preliminarily determined by analyzing standard solutions of pure analytes and confirmed in full scan (\(m\,z^{-1}\) 10-250 amu) mode of the MS detector. Optimal dwell time for each ion was 50-100 ms. The temperatures of MS interface, ion source and quadrupole were 250, 230 and 150 \({}^{\circ}\)C, respectively.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Retention Time**} & \multirow{2}{*}{**Group No.**} & \multirow{2}{*}{**Analyte**} & \multicolumn{2}{c}{**Quantification Ion \(m\)**} & \multirow{2}{*}{**Confirmion Ions \(m\)**} & \multirow{2}{*}{**Group Start Time**} \\  & & **(min)** & & & & **(min)** \\ \hline
1 & 5.1 & & & 2,2,4-Trimethylnetane & 57 (100) & \(56,41\) (50) & \\
2 & 5.5 & & \(n\)-Heptane & 43 (50) & 41 (50) & 0 \\
3 & 9.9 & & Methyl ethyl ketone & 43 (50) & 72 (50) & \\ \hline
4 & 10.4 & & & Methylence chloride & 49 (100) & 84 (50) & \\
5 & 10.8 & & Benzene & 78 (100) & & 10.2 \\
6 & 11.8 & & \(n\)-Decane & 142 (100) & & \\ \hline
7 & 12.6 & & & 1,1,2,2-Tetrachloroethylene & 166 (50) & 164 (50) & \\
8 & 13.1 & & Toluene & 91 (100) & & \\
9 & 13.5 & & 1,2-Dichloroethane & 62 (100) & 64 (50) & \\
10 & 13.8 & & \(n\)-Undecane & 156 (100) & & 12.2 \\
11 & 14.9 & & Ethylenebenzene & & \\
12 & 15.0 & & \(n\)-Xylene & 106 (100) & & \\
13 & 15.1 & & \(p\)-Xylene & & & \\ \hline
14 & 15.7 & & & Propylbenzene & 105 (100) & \\
15 & 15.9 & & \(\circ\)-Xylene & 106 (50) & & \\
16 & 16.5 & & 4 & Chlorobenzene & 112 (100) & 77 (50) & 15.5 \\
17 & 17.0 & & 1,3,5-Trimethylbenzene & & 105 (100) & \\
18 & 17.7 & & 1,2,4-Trimethylbenzene & & \\
19 & 18.1 & & 3-Picoline & 93 (100) & 66 (50) & \\ \hline
20 & 23.4 & & Benzaldehyde & 77 (100) & & \\
21 & 24.8 & 5 & \(n\)-Hexadecane & 57 (100) & 43 (100) & 22.0 \\
22 & 27.9 & & & Naphthalene & 128 (100) & \\ \hline
23 & 31.0 & & & Phenol & 94 (100) & \\
24 & 33.7 & & & Acnaphhene & 153 (100) & & 30.0 \\
25 & 36.8 & & & Fluorene & 166 (100) & \\ \hline \hline \end{tabular}
\end{table}
Table 2: MS detection program of analytes in SIM mode.