## 4 Glyphosate and AMPA in Foods
### Sample Cleanup  
Foods are complex matrices that contain metallic ions, lipids, proteins, sugars, fibers, starch, and other components, which can result in significant signal suppression during chromatographic analysis of GLYP and AMPA. Consequently, the utilization of an effective sample cleanup technique following GLYP and AMPA extraction is essential for enhancing method accuracy and precision [26]. At present, solid-phase extraction (SPE) and QuEChERS are the most frequently employed cleanup strategies to mitigate the matrix effect when analyzing pesticides such as glyphosate and their derivatives (AMPA) in food samples [82; 85; 90; 91], as listed in Table 4.  
SPE adheres to principles such as liquid-solid extraction, wherein analytes are separated based on their distribution between two phases. The sample, diluted in a liquid system, is passed through a solid-phase sorbent, where the analytes are retained by the sorbent with varying degrees of affinity. Following this retention step, a washing solvent is employed to remove any non-retained impurities. Subsequently, the addition of an elution solvent disrupts the interaction between the analytes and sorbent, facilitating the analyte purification from the matrix. Various approaches, including normal phase, reversed phase, and ion exchange, can be utilized to enhance analyte retention within the SPE system. SPE has been used for GLYP and AMPA extraction from yam and grape [92; 93], guava [94], diverse fruit and vegetables [95], soy and corn [82], and beer [80]. Hydrophilic-lipophilic balanced (HLB) SPE cartridges are polymer-based universal sorbents with a sophisticated reversed-phase retention system. Their characteristics enable them to interact with various compounds, including acidic, basic, or neutral analytes. In recent years, HLB cartridges have become the standard cleanup technique for glyphosate and AMPA purification prior to chromatographic analysis. Research has supported HLB as an effective extraction strategy with satisfactory recovery rates for analyzing polar pesticides from food matrices. A study conducted on 13 different food samples utilized a PRIME HLB \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Food Sample** & **GLYP/AMPA** & \begin{tabular}{c} **Glyphosate** \\ **Recovery (\%)** \\ \end{tabular} & \begin{tabular}{c} **AMPA** \\ **Recovery (\%)** \\ \end{tabular} & \begin{tabular}{c} **Extraction** \\ **Method** \\ \end{tabular} & **Sorbent** & \begin{tabular}{c} **Retention** \\ **Mechanism** \\ \end{tabular} & **Ref.** \\ \hline Apple & & 103.1–115.6 & 84.2–105.6 & & & & & \\ Cucumber & & 97.4–112.5 & 90.5–101.4 & & & & \\ Potato & & 99.3–102.7 & 95.9–103.4 & & & & \\ Celery & & 90.2–110.5 & 89.1–99.0 & & & & \\ Grape & & 91.3–107.5 & 98.1–114.4 & & & & \\ Soybean & & 106.1–111.4 & 91.4–94.0 & & & & \\ Tea & GLYP/AMPA & 97.0–102.3 & 92.0–108.0 & SPE & PHME & Reversed & \\ Kiwi & & 87.3–105.6 & 96.0–97.5 & & HLB & phase & \\ Pumpkin & & 87.0–101.3 & 99.7–104.5 & & & & \\ Orange & & 104.4–109.2 & 88.6–100.6 & & & & \\ Lettuce & & 88.6–104.7 & 91.7–103.1 & & & & \\ Rice & & 96.0–97.2 & 91.5–103.5 & & & & \\ Wheat & & 101.5–105.5 & 91.1–98.9 & & & & \\ \hline Soybean & GLYP/AMPA & 96–98 & 96–113 & SPE & Oasis HLB & Reversed & [82] \\ Corn & GLYP/AMPA & 102 & NR & SPE & Oasis HLB & \begin{tabular}{c} Reversed \\ phase \\ \end{tabular} & [72] \\ \hline Beer & GLYP & 87.0–123.0 & & SPE & Strata-XA & \
\begin{tabular}{c} Anionic \\ exchange \\ \end{tabular} & [80] \\ \hline Egg & GLYP/AMPA & 94.12–139.3 & 96.83–106.8 & SPE & Plexa PCX &
\begin{tabular}{c} Cationic \\ exchange \\ \end{tabular} & [91] \\ \hline Sesame & & 87 & 87 & & & & \\ Lentils & & 57 & 60 & & & \\ Wheat & & 60 & 74 & dSPE & C18 & Reversed & [90] \\ Cocoa Bean & & 50 & 47 & dSPE & C18 & phase & \\ Infant Food & & 71 & 73 & & & \\ Milk & & 93 & 93 & & & \\ \hline \hline \end{tabular}  
* NR: Not reported; SPE: solid-phase extraction; dSPE: Dispersive solid-phase extraction.  
\end{table}