An analytical method is presented for the determination of chlorantraniliprole residues in crops. Chlorantraniliprole residues were extracted from crop matrixes with acetonitrile after a water soak. The extracts were passed through a strong anion-exchange (SAX) SPE cartridge stacked on top of a reversed-phase (RP) polymer cartridge. After both cartridges were rinsed and vacuum-dried, the SAX cartridge was removed, and chlorantraniliprole was eluted from the RP polymer cartridge with acetonitrile. The acetonitrile eluate was evaporated to dryness, reconstituted, and analyzed using an LC/MS/MS instrument equipped with an atmospheric pressure chemical ionization source. The method was successfully validated at 0.010, 0.10, and 10 mg/kg for the following crop matrixes: potatoes, sugar beets (tops), lettuce, broccoli, soybeans, soybean forage, tomatoes, cucumbers, oranges, apples, pears, peaches, almonds (nutmeat), rice grain, wheat grain, wheat hay, corn stover, alfalfa forage, cottonseed, grapes, and corn grain. The average recoveries from all crop samples fortified at the method LOQ ranged from 91 to 108, with an overall average recovery of 97. The average recoveries from all crop samples fortified at 10 times the method LOQ ranged from 89 to 115, with an overall average recovery of 101. For all of the fortified control samples analyzed in this study, the overall average recovery was 99.

The quick, easy, cheap, effective, rugged, and safe (QuEChERS) and the U.S. Food and Drug Administration pesticide multiresidue methods were systematically tested for the analysis of aminocyclopyrachlor, a new synthetic auxin herbicide. Results revealed that these procedures are not suitable, highlighting the need for a publicly available residue method for this new active ingredient. Such a method has been developed and is reported herein for aminocyclopyrachlor residue analysis in vegetation, including white pine, Norway spruce, grass forage, and grass hay. Aminocyclopyrachlor residues were purified from plant tissue extracts by filtration through SPE cartridges with strong anion exchange stationary phases and analyzed using LC/MS/MS. This method was validated at five laboratories across the United States; their results were compared to evaluate reproducibility and ruggedness. The method LOQ was 0.01 mg/kg (ppm) and the LOD 0.003 mg/kg (ppm) for the matrixes tested. A qualitative procedure to confirm the molecular identity of residues based on retention time measurements and ion transition peak area ratios (m/z 214 --> 681m/z 214 --> 101) is also presented.