## 2 Materials and Methods  
### Samples  
The analyzed samples consist of cotton, synthetic fibers, or a blend of both. They were purchased from various retailers and differ in origin and color. The details are provided in Table 1. All the samples listed in the table were analyzed using GC-MS, while only a subset (indicated by the superscript \"a\") was analyzed using ICP-MS.  
Headspace Solid-Phase Micro-Extraction Gas Chromatography-Mass Spectrometry ((HS)-SPME GC-MS) Analysis  
The SPME fiber used in this work was coated with divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS), with a 50/30 \(\upmu\)m thickness (Supelco, Belle-fonte, PA, USA). A 1 cm side square of tissue was cut into pieces to approximately half-fill a 4 mL vial equipped with a Mininert cap for SPME. The vial was kept at 150 \({}^{\circ}\)C in an oil bath for 15 min. The fiber was then introduced into the vial and exposed for 15 min to the headspace of the sample. The desorption of the extracted volatiles was performed by placing the fiber into the injection port of the gas chromatograph at 270 \({}^{\circ}\)C for 5 min. After each analysis, the fiber was conditioned in the GC injection port at 270 \({}^{\circ}\)C for 5 min, after which a blank run was recorded to verify the fiber cleaning. The analyses were carried out on a Trace 1300 ISQ LT GC-MS from Thermo Fisher Scientific (Waltham, MA, USA). The GC apparatus was equipped with a split/splitless injector with a SPME liner inside. All injections were performed in splitless mode. A J&W capillary column HP5 MS (5% phenyl- polymethylsiloxane, 30 m, 0.25 mm i.d., and 0.25 \(\upmu\)m film thickness) was used and the carrier gas was helium 5.5 IP, supplied at a flow rate of 1.1 mL/min. GC separation was achieved using the following column oven temperature program: an initial temperature of 40 \({}^{\circ}\)C for 5 min, and then increasing to 250 \({}^{\circ}\)C at 7 \({}^{\circ}\)C/min, and at the end, raised to 270 \({}^{\circ}\)C at a rate of 75 \({}^{\circ}\)C/min and held for 2 min. The EI-ion trap mass spectrometer operated at the following conditions: 70 eV ionization energy; 25-700 \(m/z\) range; 0.2 s scan cycle time; 260 \({}^{\circ}\)C transfer line temperature; 270 \({}^{\circ}\)C ion source temperature. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sample** & **Origin** & **Composition** & **SPME Fiber** \\ \hline TESS\_96A & China & 100\% cotton & DVB/CAR/PDMS \\ TESS\_96B & China & 100\% cotton & CAR/PDMS \\ TESS\_96C & China & 100\% cotton & DVB/CAR/PDMS \\ TESS\_96D & China & 100\% cotton & DVB/CAR/PDMS \\ TESS\_97A & China & 100\% cotton & DVB/CAR/PDMS \\ TESS\_97B & China & 100\% cotton & DVB/CAR/PDMS \\ TESS\_97C & China & 100\% cotton & DVB/CAR/PDMS \\ TESS\_97D & China & 100\% cotton & DVB/CAR/PDMS \\ TESS\_98A \({}^{\text{a}}\) & China & 100\% cotton & DVB/CAR/PDMS \\ TESS\_98B \({}^{\text{a}}\) & China & 100\% cotton & DVB/CAR/PDMS \\
2 TESS\_99A \({}^{\text{a}}\) & China & 100\% cotton & DVB/CAR/PDMS \\
2 TESS\_99B \({}^{\text{a}}\) & China & 100\% cotton & DVB/CAR/PDMS \\ TESS\_100A \({}^{\text{a}}\) & China & 100\% cotton & DVB/CAR/PDMS \\ TESS\_100B \({}^{\text{a}}\) & China & 100\% cotton & DVB/CAR/PDMS \\
2 CANOV\_BLUA \({}^{\text{a}}\) & Egypt & 100\% cotton & DVB/CAR/PDMS \\
2 CANOV\_BLUB \({}^{\text{a}}\) & Egypt & 100\% cotton & DVB/CAR/PDMS \\ CANOV\_ROSSA \({}^{\text{a}}\) & Egypt & 100\% cotton & DVB/CAR/PDMS \\ CANOV\_ROSSB \({}^{\text{a}}\) & Egypt & 100\% cotton & DVB/CAR/PDMS \\ CALZ\_BIANCO\_A \({}^{\text{a}}\) & Italy & 100\% cotton & DVB/CAR/PDMS \\ CALZ\_BIANCO\_B \({}^{\text{a}}\) & Italy & 100\% cotton & DVB/CAR/PDMS \\ CALZ\_NRA \({}^{\text{a}}\) & Italy & 95\% cottone, 5\% elastane & DVB/CAR/PDMS \\ CALZ\_NRB \({}^{\text{a}}\) & Italy & 95\% cottone, 5\% elastane & DVB/CAR/PDMS \\ CAMICIA\({}^{\text{a}}\) & Italy & 80\% cottone, 20\% elastane & DVB/CAR/PDMS \\ CAMICIA\({}^{\text{b}}\) & Italy & 80\% cottone, 20\% elastane & DVB/CAR/PDMS \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Samples analyzed using (HS)-SPME GC–MS.