## 4 Glyphosate and AMPA in Foods
### Sample Cleanup

Table 4: Sample cleanup strategies for recovery of glyphosate and AMPA from foods. cartridge in a non-retentive SPE protocol for glyphosate and AMPA determination [85]. Oasis HLB cartridges are also widely employed in sample preparation, with studies reporting glyphosate recovery percentages in soybean (96-98%), corn (96-98%), and oat (102%). AMPA recovery percentages have been reported in soybean and corn (96-113%) [96]. Dispersive solid-phase extraction (dSPE), also known as QuECHERS, is an alternative methodology initially developed for pesticide residue analysis in fruits and vegetables [90]. The primary distinction from classical SPE cartridges is that in dSPE, the sorbent is presented as a loose powder in predetermined quantities. In this context, polar pesticides such as GLYP are mainly analyzed using single-residue methods instead of multi-residue procedures [97]. Traditional QuECHERS methodologies use C18 or PSA (primary or secondary amines) as retention sorbents, acetonitrile as the sample diluent, and MgSO\({}_{4}\) for sample cleanup. Due to the chelating nature of GLYP and AMPA, the addition of MgSO\({}_{4}\) is not recommended [96]. It is mainly recommended as a cleanup strategy for food samples containing a single type of pesticide. Official guidelines, such as QuEPPe-PO, establish the use of dSPE with C18 sorbent as the standard for GLYP and AMPA cleanup in food samples [26]. Notwithstanding regulatory guidelines, several researchers have reported lower recovery rates with the C18-based dSPE extraction technique compared to SPE cartridges. [PERSON] et al. [90] evaluated the QuEPPe-PO method for the analysis of glyphosate and AMPA, reporting recovery percentages of 60-93% for glyphosate and 47-93% for AMPA. These recoveries were lower than those reported by other researchers who utilized SPE cartridges to analyze similar samples. Other extraction methods for recovering GLYP and AMPA from food matrices have been explored with or without applying cleanup strategies in combination with the QuPPe method [26]. For instance, [PERSON] et al. [98] extracted GLYP from honey, fish, and beer samples using ultrasound-assisted extraction (15 min) and acidified water (1%) and methanol (7:3) before cold centrifugation (4 \({}^{\circ}\)C) at 2500\(\times\)\(g\) for 10 min, prior to IC-HRMS analysis, with an LOQ of 43, 51, and 65 ug/kg, respectively. Similarly, ultrasound-assisted extraction (10 min) using water as solvent was applied for extracting GLYP from cereals [99]. Additionally, [PERSON] et al. [100] homogenized food samples (melon, pea, pepper, or pineapple) with a mixture of water and methanol (1:1) before centrifuging at 2500\(\times\)\(g\) for 10 min, prior to IC-MS/MS analysis, with an LOD of 25 ug/kg. Similarly, centrifugation and acidified methanol at 1% have been used for extracting GLYP from fruits and vegetables (4000\(\times\)\(g\) for 5 min) [66], oil (3700\(\times\)\(g\) for 10 min) [101], and rice and corn (4000\(\times\)\(g\) for 5 min) [83]. The selection of the most appropriate cleanup strategy should prioritize the reduction of potential interferences within the sample matrix. An inadequate extraction process can lead to matrix effects that either enhance or suppress the analytical response, leading to inaccurate results. Furthermore, a non-optimized extraction protocol may compromise analyte recovery, thereby reducing the sensitivity and detection capability of the analytical technique. Based on this, parameters such as recovery rates are critical when comparing different cleanup strategies. SPE is a highly selective, specific, and robust cleanup strategy that can be tailored to a wide range of food matrices. It is particularly useful for analyzing complex samples, especially those with high levels of fat, sugar, or pigments. The use of reversed-phase cartridges effectively reduces non-polar interferences, making them suitable for lipid-rich samples. Conversely, ion-exchange cartridges are highly recommended to minimize ionic interferences, such as metal ions.