Metribuzin is a pre- and post- emergence herbicide on the EURL (European Union Reference Laboratory) Target Pesticide List for the EUPT-CF9 2015 (European Union Proficiency Test for Cereals and Feeding stuff). Metribuzin disrupts photosynthesis in plants growing near food crops such as potatoes, tomatoes and sugar came. Obelisc R and Primesep 100 were used to retain Metribuzin using multiple modes of separation. Obelisc R contains a long hydrophobic chain and ion-pairing groups, while Primesep 100 contains embedded acidic ion-pairing groups. Method is LC/MS compatible and can be used with similar conditions to retain many pesticides.