# Exploring the Potential of Microextraction in the Survey of Food Fruits and Vegetable Safety
## 2 Extraction Approaches Used to Assess Food Safety
### Conventional Extraction Approaches  
Table 1 shows works found in the literature since 2018 using conventional extraction techniques such as SLE, LLE, magnetic solid-phase extraction (MSPE), QuECHERS, salting-out assisted liquid-liquid extraction (SALE), SFE, UAE, and ultra-high pressure supercritical-fluid extraction (UHPSFE). Overall, the methods proposed showed high sensitivity, with low limits of detection (LODs) reported in most of them. Pesticides were the most frequently reported contaminant in the articles discussed (Table 1). [PERSON] et al. [74] extracted thiazolprid, a neonicotinoid insecticide, from 5 g of different fruit and vegetable samples, using SLE/SALE/dSPE as the extraction approach. Good recovery values were retrieved (78.3-92%), as well as acceptable repeatability and reproducibility (reported values below 4.74%). Similarly, [PERSON] et al. [77] developed an extraction method for azoxystrobin, difenoconazole, and chlorothalonil employing SLE with a low-temperature partition (LTP). The determination of these pesticides was carried out in bell pepper samples and residual concentrations of 0.12, 0.18, and 1.73 mg kg\({}^{-1}\) were obtained, respectively. Maldin, chlororyrifos, and profenofos were determined in red apples and purple grapes through SLE/SPE with methyltrimethoxysilane (MTMOS-CPTES), an extraction method developed by [PERSON] et al. [79]. Good recovery values were obtained (88.3-120.7%) with low standard deviations (1.6-3.3%) compared to the commercial octadecyl silica sorbent (70.3-100.2% \(\pm\) 6.3-8.8%). SFE using supercritical carbon dioxide (SC-CO\({}_{2}\)) as a solvent is a very efficient alternative due to the beneficial characteristics of the solvent, thus, favouring its low consumption [80]. [PERSON] et al. [80] used this method to extract four insecticides under a heating temperature of 80 \({}^{\circ}\)C and a high elution volume (4 mL in total). The solvent selection is crucial to obtain a green extraction method. For this reason, green solvents such as deep eutectic solvents (DESs) are being used to replace conventional solvents, which are often more toxic [81]. Until now, DESs have rarely been used as solvents in the UAE for the extraction of analytes in food samples because expensive tandem MS instruments are often required [82; 83]. However, there are some notable exceptions. [PERSON] et al. [84] used a UAE/DES-MSPE method for the extraction of seven pesticides in apple, pear, carrot, and cucumber samples, followed by HPLC-UV analysis, and obtained good LOD values (0.02-0.05 \(\upmu\)g mL\({}^{-1}\)). It is important to highlight that UAE has a lower solvent and time consumption than other conventional extraction approaches, increasing the recovery rates of the target analytes. This is possible because the US enhances the interaction between the solvent and the matrix and lower solvent volumes provide satisfactory results [84]. Similarly, [PERSON] et al. [85] also achieved good LOD values (0.05-0.2 \(\upmu\)g mL\({}^{-1}\)) for the extraction of two fungicides and one insecticide in apple, grape, and tomato samples, using a UAE/DES-LLE approach followed by HPLC-DAD analysis. The QuECHERS coupled with dSPE is a salting-out extraction procedure originally proposed by [PERSON] et al. [86] for the multi-residue detection of pesticides in food products. It was rapidly adopted as a standard extraction procedure due to the simplicity of its use (reviewed in [78]). [PERSON] et al. [87] used this methodology for the extraction of 82 pesticides in organic carrots. LODs between 0.3-0.5 ug kg\({}^{-1}\) were obtained through HPLC-HRMS analysis. The results showed that benidocarb was detected at high concentrations (199.11 ug kg\({}^{-1}\)) above its MRL. Chlorypriphos (43.20 ug kg\({}^{-1}\)) and amitraz (11.22 ug kg\({}^{-1}\)) were also detected. [PERSON] et al. [88] compared QuEChERS/dSPE and QuEChERS/dSLE. The authors observed that the dSFE clean-up version retrieved a higher sensitivity.