Highly polar pesticides (glyphosate, AMPA, fosetyl-aluminum, etc.) are particularly challenging analytes to study. They have very low extractability in typical multiresidue methods, such as QuEChERS, ethyl acetate, and miniLuke. Additionally, their retention in the reversed-phase liquid chromatography columns typically used for pesticide analysis is generally poor and unstable. Using highly polar solvents, such as methanol or methanol and water, can help solve problems with extractability. One approach to addressing poor retention is derivatization. However, derivatization is time consuming and not all compounds can be derivatized.
As noted in the last European Food Safety EFSA 2014 report, these analytical challenges mean that many routine laboratories do not have the capabilities necessary to determine polar pesticide compounds.