## 2 Results and Discussion
### Comparison with Previous Studies  
The pesticide concentrations shown in Table 2 were compared to results reported in previous studies about the determination of pesticide traces in water samples, as can be seen in Table 3. The selected references described the investigation of pesticide residues in water samples by microextraction techniques followed by GC-MS analysis. The pesticide levels found in the examined samples are in the range of 42.2-155.9 mg mL\({}^{-1}\). These values are notably higher than those reported for the same pesticides in water samples collected in different regions of the World, which were between 0.069 and 3.52 ng mL\({}^{-1}\). This significant difference could be explained by the fact that all the surface and groundwater samples examined in the present study were brought from an agricultural area, with a high probability of the presence of pesticides. On the other hand, a comparison was carried out between some previous studies on pesticide analysis using SPME techniques with the results obtained in the present work with homemade needles coated with PDMS. All these studies highlighted the simplicity and great capacity of the extraction methods based on SPME for the determination of pesticides in various samples. For instance, a study authored by [PERSON] et al. investigated the pesticide residues in rice using a series of commercial SPME fibers. The rice was extracted for 40 min at a temperature of 80 \({}^{\circ}\)C, and the desorption time was 10 min. Several pesticides were identified and quantified in rice, including tebuconazole. The validation results showed limits of detection of between 0.46 and 5.9 and RSD% values in the range \begin{table}
\begin{tabular}{l c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Pesticide**} & \multicolumn{8}{c}{**Water Samples**} \\  & & & & & **(ng mL\({}^{-1}\))** & & & & & \\ \cline{2-11}  & S1 & S2 & S3 & S4 & S5 & S6 & S7 & S8 & S9 & S10 \\ \hline
**Diazmon** & ND & ND & ND & ND & ND & ND & ND & ND & ND & ND \\
**Chloropyriphos-methyl** & ND & ND & ND & ND & ND & ND & ND & ND & ND & ND \\
**Primiphos-methyl** & 42.2 & ND & ND & ND & ND & ND & ND & ND & ND & ND \\
**Aldrin** & 155.9 & ND & ND & ND & ND & ND & ND & ND & ND & ND \\
**Malathion** & ND & ND & ND & ND & ND & ND & ND & ND & ND & ND \\
**Chloropyrifos** & ND & ND & ND & ND & ND & ND & ND & ND & ND & ND \\
**Profenofos** & ND & ND & ND & ND & ND & ND & ND & ND & ND & ND \\
**Ethion** & 80.1 & 87.9 & ND & ND & ND & ND & ND & ND & ND & ND \\
**Tebuconazole** & ND & ND & ND & ND & ND & ND & ND & 85 & ND & ND & ND \\
**Fenpropathrin** & ND & ND & ND & ND & ND & ND & 132.4 & ND & ND & ND & ND \\
**\(\lambda\)-Cyhalothrin** & ND & ND & ND & ND & ND & ND & ND & ND & ND & ND \\
**\(\lambda\)-Cyhalothrin (iso)** & ND & ND & ND & ND & 114.8 & ND & ND & ND & ND & ND \\
**Deltamethrin** & ND & ND & ND & ND & ND & 68.9 & ND & ND & ND & ND \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Concentration and detection ranges of target pesticides in 10 water samples. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Pesticides**} & \multicolumn{2}{c}{**Present Work**} & \multicolumn{2}{c}{**Previous Studies**} \\  & **Concentration** & **(ng mL\({}^{-1}\))** & **Sample** & **Concentration** & **Water Type** & **Ref.** \\ \hline Pirrimiphos-methyl & 42.2 & S1 & 0.069–0.230 & River & [34] \\ \hline Aldrin & 155.9 & S1 & 0.257 & River & [51] \\  & 87.9 & S2 & 0.14 & Surface & [34] \\ \hline \(\lambda\)-Cyhalothrin & 114.8 & S5 & 0.16 & Well & [34] \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Comparison of real sample concentration with previous studies. of 1.3-19% [53]. Similarly, [PERSON] et al. have developed a method for the extraction and determination of pesticides in bovine milk samples by HS-SPME. The extraction time was 90 min, the extraction temperature was 80 \({}^{\circ}\)C, and the desorption time was 15 min. They could reach LOD values in the range of 0.2-0.4 ng mL\({}^{-1}\), while the RSD values were between 2 and 24.6% [54]. Additionally, [PERSON] et al.