## 2 Experimental Section
### GC-MS Analysis  
Initially five different injection port temperatures were tested for _TI_IPS7414 using DVB/CAR/PDMS fibers; 110 \({}^{\circ}\)C, 160 \({}^{\circ}\)C, 190 \({}^{\circ}\)C, 220 \({}^{\circ}\)C, and 250 \({}^{\circ}\)C. Of these 110 \({}^{\circ}\)C, 160 \({}^{\circ}\)C, and 250 \({}^{\circ}\)C were selected to be tested for all the fibers. Three biological replicates were performed for each injection port temperature combined with the selected types of fibers. This was repeated for _Tp_GAS, _Tg_TPS1 and _Tg_TPS2. A purified germacrone standard, purchased from International Laboratory USA, was included as a further test.  
Samples were analyzed on a Shimadzu GCMS-QP2010 plus. The column used was an Agilent HP-5 MS UI, fused Silica capillary column 20 m, 0.18 mm diameter \(\times\) 0.18 \(\upmu\)m film thickness, inserted directly into the ion source of the MS. The pressure was kept at 66.7 kPa, giving a column flow of 1 mL/min. The oven temperature was set to 60 \({}^{\circ}\)C for 3 min, and then increased to 160 \({}^{\circ}\)C with a rate of 7 \({}^{\circ}\)C/min. The temperature was further increased to 300 \({}^{\circ}\)C with a rate of 50 \({}^{\circ}\)C/min and held for 5 min and finally increased to 320 \({}^{\circ}\)C with 50 \({}^{\circ}\)C/min and maintained for 3 min. The carrier gas was H2 and the ionization electron energy was 70 eV. The ion source temperature was 230 \({}^{\circ}\)C with an interface temperature of 280 \({}^{\circ}\)C. The total run time was 28.49 min. SPME fibers were conditioned at 240 \({}^{\circ}\)C for 20 min after each test.  
A C7-C30 standard purchased from Sigma-Aldrich, Denmark was used to calculate retention indices (\(R_{\mathrm{i}}\)). All data were analyzed using the Shimadzu software Lab Solutions, GCMS Solutions version 2.50 SU3, with the 2008 libraries provided by NIST and Wiley. _TI_TPS7414 chromatograms were integrated in the range 10 to 15 min, since this included all detected sesquiterpenes. _Tg_TPS2 chromatograms were integrated in the range 10 to 17 min. _Tp_GAS chromatograms were integrated in the range 11 to 14 min. In a few cases where the separation of peaks could not be done automatically, peak separation was performed manually.  
\begin{table}
\begin{tabular}{l|l|l|l|l|l} \hline
**Thickness and Fiber** & **Fiber core** & **Molecular mass** & **Recommended for** & **Absorbent/** & **Purchasing** \\
**coating** & & **range (Da)** & & **adsorbent** & **information** \\ \hline
100 \(\upmu\) PDMS & Fused Silica & 60–275 & volatiles & Absorbent & 57341-U \\ \hline
65 \(\upmu\)PDMS/DVB & Fused Silica & 50–300 & volatiles, amines, nitro-aromatic compounds & Adsorbent & 57345-U \\ \hline
85 \(\upmu\)m CAR/PDMS & StableFlex & 30–225 & gases, low molecular weight compounds & Adsorbent & 57295-U \\ \hline
50/30 \(\upmu\)m & StableFlex & 40–275 & volatiles, semi-volatiles, C3-20 & Adsorbent & 57298 \\ DVB/CAR/PDMS & 1 cm & & semi-volatiles, C3-20 & & \\ \hline Polyacrylate & Fused Silica & 80–300 & polar semi-volatiles & Absorbent & 57294-U \\ \hline \end{tabular}
\end{table}
Table 2: Overview and describtion of the tested fibres, including their product number at Supelco, Sigma-Aldrich.