The use of dispersive pipet extraction (DPX) tips for the sample cleanup of apples, pears, and oranges in the analysis of formetanate HCI.

The U.S. Environmental Protection Agency Analytical Chemistry Laboratory evaluated the effectiveness of dispersive pipet extraction (DPX) tip cleanup and compared the results with the Quick, Easy, Cheap, Effective, Rugged, and Safe dispersive tube cleanup for the sample preparation of three different fruit matrixes analyzed for formetanate HCI (FHCI). Using LC/MS/MS, the target LOD and the LOQ achieved for FHCI with dispersive tubes, 0.1 and 0.3 ng/g, respectively, were similar to the DPX tip sample cleanup. Recoveries at the LOQ ranged from 94 to 109%. A set of 20-40 samples could be prepared in one working day by one chemist.