4-(2,4-dichlorophenoxy)butyric acid or 2,4-DB is a herbicides used in alfalfa, peanuts, and soybean production. 2,4-DB selectively controls broadleaf weeds inhibiting growth at the root and stem tips. It is considered slightly toxic, as is its metabolite 2,4-D. The EURL (European Union Reference Laboratory) included 2,4-DB in an analysis of acidic pesticides using QuEChERS methodology. Primesep 100 and Obelisc R were used to retain and separate 2,4-DB from impurities. Method is LC/MS compatible and developed to be used for many pesticides.