Analytical method for the determination of cyromazine and melamine residues in soil using LC-UV and GC-MSD

A method is reported for the determination of cyromazine and melamine resid ues in soil. Soil samples are extracted twice via mechanical shaking, each time with 70% acetonitrile/30% 0.050 M ammomium carbonate for 30 min. An al iquot portion of the pooled extracts is subjected to strong cation exchange (SCX) purification on AG 50W-X4 resin. Final analysis is accomplished usin g liquid chromatography-ultraviolet (LC-UV) detection at a wavelength of 21 4 nm. Confirmatory analyses can be performed using gas chromatography-mass selective detection (GC-MSD) in the selected ion monitoring (SIM) mode. The limit of detection (LOD) is 2.5 ng injected and the limit of quantificatio n (LOQ)! is 10 ppb when using LC-W for the analysis of N-cyclopropyl-1,3,5- triazine-2,4,6-triazine (cyromazine) and 1,3,5-triazine-2,4,6-triamine (mel amine). The LOD is 0.050 ng injected and the LOQ is 10 ppb when using GC-MS D for confirmatory analyses. The mean procedural recoveries were 97 and 95% and the standard deviations were 16 and 11% for cyromazine and melamine, r espectively (n = 24), when using LC-UV. The mean procedural recoveries were 107 and 92% and the standard deviations were 9.9 and 16% for cyromazine an d melamine, respectively (n = 29), when using GC-MSD. The method validation study was conducted under U.S. EPA FIFRA Good Laboratory Practice Guidelin es 40 CFR 160. The method also passed an Independent Laboratory Validation (ILV) as per U.S. EPA FIFRA Subdivision N.