## 3 Experimental Part
### GC-MS/MS Analysis  
Samples were analyzed in dynamic multiple reaction monitoring (dMRM) mode. The dMRM windows were determined according to the retention times of the analytes from the 16 PAH mix and 5 deuterated PAH solution. To identify PAHs for most of the compounds, one target and one qualifier transition ion were monitored (Table 2), and quantification was carried out based on target ion responses.  
After the optimization, the following set up and parameters were used for GC-MS/MS analysis:  
- GC Column: DB-EUPAH capillary column: 20 m \(\times\) 180 \(\mu\)m \(\times\) 0.14 \(\mu\)m, 5% phenyl methyl siloxane (Agilent 121-9627);  
- Liner: 800 \(\mu\)L Splitless, double taper, Ultra Inert (Agilent 5190-3983);  
- Carrier gas: Ultrapurified helium 99,999%, 1 mL/min;  
- Injection type: pulsed splitless, 70 psi until 1.9 min, then 22.292 psi;  
- Inlet temperature: 325 \({}^{\circ}\)C;  
- Oven temperature: 70 \({}^{\circ}\)C(1,16 min), 70 \({}^{\circ}\)C/min to 180 \({}^{\circ}\)C (0 min), 7 \({}^{\circ}\)C/min to 230 \({}^{\circ}\)C (6 min), 40 \({}^{\circ}\)C/min to 280 \({}^{\circ}\)C (5 min), 25 \({}^{\circ}\)C/min to 330 \({}^{\circ}\)C (5 min);  
- Injection volume: 2.5 \(\mu\)L;  
- Mass spectrometer quadrupole temperature: 150 \({}^{\circ}\)C;  
\begin{table}
\begin{tabular}{c c c c c c} \hline
**Compound** & **Rt (min)** & **Transition** & **Qualifier** & **LOD (ng/L)** & **LOQ (ng/L)** \\ \hline Nph-d8 & 2.871 & 136 \(\to\) 136 & - & \textless{}0.06 & \textless{}0.06 \\ Nph & 2.883 & 128 \(\to\) 102 & 128 \(\to\) 127 & \textless{}0.06 & \textless{}0.06 \\ Ace & 4.012 & 152 \(\to\) 150 & 152 \(\to\) 151 & \textless{}0.06 & \textless{}0.06 \\ Ace-d10 & 4.086 & 162 \(\to\) 160 & - & \textless{}0.06 & \textless{}0.06 \\ Acy & 4.124 & 154 \(\to\) 152 & 153 \(\to\) 152 & \textless{}0.06 & \textless{}0.06 \\ FI & 4.637 & 166 \(\to\) 165 & 166 \(\to\) 163 & \textless{}0.06 & \textless{}0.06 \\ Ph & 6.331 & 178 \(\to\) 176 & 178 \(\to\) 152 & \textless{}0.06 & 0.06 \\ Ph-d10 & 6.346 & 188 \(\to\) 188 & - & \textless{}0.06 & \textless{}0.06 \\ Ant & 6.387 & 178 \(\to\) 176 & 178 \(\to\) 152 & 0.06 & 0.09 \\ Flt & 9.312 & 202 \(\to\) 200 & 202 \(\to\) 201 & \textless{}0.06 & 0.18 \\ Py & 10.168 & 202 \(\to\) 200 & 202 \(\to\) 201 & \textless{}0.06 & 0.16 \\ B[a]A & 16.193 & 228 \(\to\) 226 & 228 \(\to\) 224 & 0.98 & 1.18 \\ Chr-d12 & 16.438 & 240 \(\to\) 236 & 118 \(\to\) 116 & 0.24 & 1.76 \\ Chr & 16.550 & 228 \(\to\) 226 & 228 \(\to\) 224 & 0.30 & 0.90 \\ B[b]F & 16.460 & 252 \(\to\) 250 & 250 \(\to\) 248 & \textless{}0.06 & 0.46 \\ B[k]F & 19.510 & 252 \(\to\) 250 & 250 \(\to\) 248 & \textless{}0.06 & 0.69 \\ Benzo[a]/[e]pyrene & 20.952 & 252 \(\to\) 250 & 250 \(\to\) 248 & 1.50 & 3.65 \\ Per-d12 & 21.350 & 264 \(\to\) 260 & - & 0.98 & 1.22 \\ I [cd]P & 24.252 & 276 \(\to\) 274 & 138 \(\to\) 124 & 0.63 & 4.00 \\ D[ah]A & 24.291 & 278 \(\to\) 276 & 125 \(\to\) 124 & 1.28 & 4.42 \\ B[ghi]P & 24.809 & 276 \(\to\) 274 & 274 \(\to\) 272 & 0.46 & 3.65 \\ \hline \end{tabular}
\end{table}
Table 2: GC-MS/MS—retention times, QQQ transitions used for detection of targeted compounds and internal standards and obtained limits of detection (LOD) and quantification (LOQ).  
Mass spectrometer source temperature: 340 \({}^{\circ}\)C.  
Separate calibration curves were created for each of the 16 PAH compounds and 5-D PAHs in the range of 0.06-1000 ng/mL concentrations. The limit of detection (LOD) and limit of quantification (LOQ) values were calculated in Mass Hunter Agilent Software based on the signal to noise ratio using the RMS (root mean square) noise algorithm. The LOD values were found to be from <0.06 to 1.5 ng/L, and the LOQ values were <0.06-4.42 ng/L depending on the individual compound (Table 2). The final concentration was obtained as a mean of 2 injections by use of internal standard method calculation.