## 4 Discussion  
The formulation of multi-residue methodologies for the quantification of hydrophobic pesticides within oil matrices poses a rigorous analytical hurdle. To uphold optimal chromatographic system efficacy, meticulous sample decontamination from interfering agents is paramount [19]. This study assessed the extraction efficiency of 294 pesticides from a high-fat matrix-unrefined olive oil. A key element of the extraction is the addition of n-hexane. Previously, several extraction methodologies utilizing this solvent were developed; however, the range of analyzed compounds was not as extensive [20; 21]. The main analytical challenge during chromatographic analysis of pesticide residues is the matrix effect. To minimize the matrix influence, [PERSON] et al. employed a eutectic solvent consisting of thymol and vanillin (1:1) deep eutectic solvent (DES), and utilized a mixture of acetonitrile and DES. The initial extraction included a 4 mL addition of n-hexane, similar to the presented procedure. The addition of n-hexane significantly improves the extraction of non-polar pesticides. The researchers removed the upper layer of n-hexane, and further analysis was based on utilizing the potential of the eutectic mixture. The use of an acetonitrile: DES (1:1) mixture significantly increased the peak height in chromatography and reduced the intensity of noise. The recovery for 16 pesticides ranged from 63.1% to 119.4% [22]. In another study, the QuEChERS method was implemented, incorporating enhancements such as the use of d-SPE with EMR-Lipid(tm) as the second purification step after freezing at \(-\)76 \({}^{\circ}\)C. Recoveries of 70-120% and a mean RSD of 4.0% were achieved for 177 pesticides, which constituted 83% of the total number of pesticides investigated [23]. Similar results were obtained by [PERSON] et al. using a specific EMR-Lipid purification sorbent. Recoveries in the range of 70-120% were achieved for 91% of the compounds out of 165 pesticides tested. The use of other purification salts did not yield such significant results [24]. The EMR-Lipid dSPE cleaning vial was introduced to the market in 2015, containing specially developed sorbents that interact specifically with matrix components. The effectiveness of cleaning oily matrices was also confirmed by [PERSON] et al. (2019) using the EMR-Lipid dSPE cleaning cartridge. Forty-six pesticides were tested, of which \(>\)95% achieved an average recovery of \(>\)70% and RSD \(<\) 15% [19]. In another study focusing on the determination of polar pesticide residues using HILIC-TOFMS, an attempt was made to add n-hexane and saturated naphtha ether with acetonitrile during the extraction procedure to avoid interferences from non-polar compounds. However, this approach was rejected due to the lack of a significant effect in a subsequent analysis using HILIC-TOFMS [25]. Extraction using the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method and its modifications is chosen by many researchers for the preparation of analytical sample extracts. Sample extraction in most proposed analytical methods occurs via a liquid-liquid extraction (LLE) technique using a solvent mixture of n-hexane, acetonitrile, and saturated naphtha ether. However, a drawback of this method is the significant co-extraction of interfering substances. It is common practice to freeze the sample to remove lipid components; however, this may decrease the solubility of analytes at low temperatures. Extraction using dSPE salts is also not a suitable choice for matrices with high fat contents due to the lack of selectivity in lipid removal [26; 27]. [PERSON] et al. (2024) used the QuEChERS extraction method, and 65 pesticides met the validation requirements, but the analytical scope of the method is too narrow to meet EU requirements [28]. Although the matrix effect was reduced in the presented method, this issue was not completely eliminated. [PERSON] et al.