4-CPA Analysis on Obelisc and Primesep Mixed-Mode Columns
4-CPA (4-Chlorophenoxyacetic acid) is a synthetic pesticide that mimics plant hormones called auxins. A single residue method for the EURL (European Union Reference Laboratory) was developed for 4-CPA and other acidic compounds using QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) methodology. Retention of 4-CPA was controlled on both Obelisc R and a 3 micron Primesep 100 column of the same dimension. By using a gradient for the organic and ionic components of the mobile phase, the method is capable of separating dozens of pesticides quickly while remaining LC/MS compatible.