# Deposition Efficacy of Natural and Synthetic Antioxidants on Fabrics
## 3 Results and Discussion
### Determination of Antioxidant Concentration Deposited on Fabric  
The assessment of the amount of antioxidant deposited on fabrics is of crucial relevance in view of many possible practical applications. In this effort, a protocol for the quantification of single antioxidant deposited was developed. Samples of fabrics (weighing 10.0 mg each), were used assuming the following: (i) once deposited, the antioxidant remains attached to the fibres by electronic interactions and hydrogen bonding, i.e., wear-off is limited; and (ii) once deposited the antioxidant does not undergo any chemical changes, i.e., does not lose its antioxidant activity.  
Analysis was performed by the ABTS\({}^{\bullet+}\) decolourisation assay as shown in Table 5, on the basis of a specific calibration for the compounds under analysis in the ABTS\({}^{\bullet+}\) decolourisation assay based on a calibration obtained for PST (Figure S3 in Supplementary Materials).  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Entry** & **Fabric Sample [10** & **Treatment** & **Anti-ox Activity [\(\upmu\)g AAE per** \\
**mg]** & **Conditions** & **Fabric Portion] [\({}^{\text{a}}\)]** \\ \hline
1 & **PST-sW1\_cotton** & H2O\_mechanical & 0.37 \(\pm\) 0.22 \\
2 & **PST-sW1\_cotton** & HDL mechanical & 0.16 \(\pm\) 0.11 \\
3 & **PTT-AW1\_cotton** & H2O\_mechanical & 0.48 \(\pm\) 0.22 \\
4 & **PTT-AW1\_cotton** & HDL mechanical & 0.41 \(\pm\) 0.23 \\
5 & **PST-sW1\_cotton** & H2O & 0.42 \(\pm\) 0.11 \\
6 & **BHT\_cotton** & H2O\_mechanical & 0.18\(\pm\) 0.22 \\
7 & **BHT\_cotton** & H2O\_measurement & 0.20\(\pm\) 0.22 \\
8 & **M\_iBHPP\_cotton** & H2O\_mechanical & 0.24\(\pm\) 0.22 \\
9 & **M\_iBHPP\_cotton** & H2O\_measurement & 0.27\(\pm\) 0.22 \\
10 & **cotton** & H2O mechanical & 0.00 \(\pm\) 0.10 \\
11 & **cotton** & HDL\_mechanical & 0.00 \(\pm\) 0.10 \\
12 & **cotton** & H2O & 0.00 \(\pm\) 0.10 \\ \hline \hline \end{tabular} \({}^{\text{a}}\) The maximum semi-dispersion is adopted for the error estimation. More in detail, as can be seen in Table 2, entries 1 and 5, the values obtained for the measurements show that there is not a substantial difference between fabrics treated industrially or in the laboratory. Noteworthy, combined data analysis shows a larger relative variance for mechanically treated samples. This fact could be explained by a non-homogenous tannin deposition especially in case of mechanical treatment (see below).  
\end{table}
Table 4: Antioxidant activity data obtained for cotton fabric samples treated with pine tannins.  
As can be seen in Table 5, the values obtained for the measurements confirm a nonhomogeneous tannin deposition onto the fabrics as it could be expected based on the chosen deposition method, the industrial launderometer process used to treat the textiles with the chosen pine tannin under the various conditions. Hence, this non-homogenous deposition could well explain the large error observed in the antioxidant activity measurements (see Table 2). On the contrary, the deposition of commercial antioxidant species carried out manually is, as expected, homogenous.