## 2 Results
### Experimental Procedure
At the moment, trace content of metals and pesticides in foods are regulated via European Commission Regulations No 1881/2006 and No 396/2005, respectively. Regulations for dietary supplements were chosen as the nearest category to evaluate health safety requirements for wild thyme and provide maximum residue levels (MRLs). Results of analyzed pesticides levels in dried wild thyme is given in Table 7. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{4}{c}{\(p\)**-Value*} \\ \hline
**Main Effect** & **Treatment Time** & **Voltage** & **Ethanol Content** & **Treatment Type** \\ \hline pH & 0.709 & 0.092 & \textless{}0.0001 & 0.183 \\ \hline Conductivity & 0.447 & 0.426 & \textless{}0.0001 & 0.158 \\ \hline Temperature difference & 0.000 & 0.371 & 0.017 & 0.014 \\ \hline Power & 0.015 & \textless{}0.0001 & 0.290 & 0.110 \\ \hline \(Z_{p}\) & 0.374 & 0.619 & \textless{}0.0001 & 0.142 \\ \hline TPC & 0.125 & 0.324 & 0.017 & 0.735 \\ \hline DPPH & 0.023 & 0.904 & 0.623 & 0.463 \\ \hline FRAP & 0.358 & 0.423 & 0.030 & 0.531 \\ \hline Yield & 0.125 & 0.324 & 0.017 & 0.735 \\ \hline Sum UPLC-MS/MS & 0.549 & 0.977 & 0.000 & 0.427 \\ \hline Sum GC-MS & \textless{}0.0001 & 0.006 & \textless{}0.0001 & 0.332 \\ \hline \hline \end{tabular}  
* \(p\leq 0.05\) is statistically significant; TPC—total phenolic content, DPPH—2,2-diphenyl-2-picrylhydrazyl free radical assay, FRAP—ferric reducing antioxidant power assay, UPLC-MS/MS—ultra performance liquid chromatography-tandem mass spectrometry characterization, GC-MS—gas chromatography and mass spectrometry analysis.  
\end{table} 
Table 6: Analysis of covariance (ANCOVA) for pH, conductivity, temperature difference, power, TPC, FRAP, DPPH, yield of extraction and sum of all compounds measured by UPLC-MS/MS and GC-MS methods. The \(p\)-values present the statistical significance of each of the factors. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Pesticides** & **MRL (mg/kg)** & **Content (mg/kg)** \\ \hline Alachlor & 0.02 & \textless{}0.005 \\ \hline Aldrin and dieldrin (aldrin and dieldrin combined & \\ expressed as dieldrin) & 0.01 & \textless{}0.002 \\ \hline Captain (sum of captain and THPI, expressed as captan) & 0.06 & \textless{}0.020 \\ \hline DDT (sum of p,p\({}^{\prime}\)-DDT, o,p\({}^{\prime}\)-DDT, p-p\({}^{\prime}\)-DDE and p,p\({}^{\prime}\)-TDE & \\ (DDD) expressed as DDT) & 0.05 & \textless{}0.004 \\ \hline Endosulfan (sum of \(\alpha\)- and \(\beta\)-isomers and & \\ endosomalfan-sulphate expressed as endosulfan) & 0.05 & \textless{}0.002 \\ \hline Endrin & 0.01 & \textless{}0.004 \\ \hline Heptachlor (sum of heptachlor and heptachlor epoxide & \\ expressed as heptachlor) & 0.01 & \textless{}0.002 \\ \hline Hexachlorobenzene & 0.01 & \textless{}0.002 \\ \hline Hexachlorocyclohexane, \(\alpha\)-isomer & 0.01 & \textless{}0.002 \\ \hline Hexachlorocyclohexane, \(\beta\)-isomer & 0.01 & \textless{}0.002 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Residue levels and maximum residue levels (MRLs) of pesticides (mg/kg) in wild thyme sample. Results of residue levels of metals found in dried wild thyme and selected extracts are given in Table 8. Due to possible abrasion of electrodes during the treatment with HVED, content of metals was analyzed also in wild thyme extract obtained by HVED. For this purpose, extract TN8 was chosen that was treated with highest voltage (25 kV), nitrogen, for longer time (9 min) and highest ethanol content (50%), since highest abrasion is expected in such extract.