Abstract An analytical method applying ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was validated for the determination of aflatoxins M2, M1, G2, G1, B2, B1, deoxynivalenol, ochratoxin A, fumonisins B1 and B2, hydrolyzed fumonisins B1 and B2, zearalenone and sterigmatocystin in crackers. The obtained recoveries (70 to 110%) and relative standard deviations (< 13%) were considered satisfactory. Method limits of quantification ranged from 0.20 µg kg-1 (sterigmatocystin) to 12.27 µg kg-1 (deoxynivalenol). The validated method was then applied for mycotoxin determination in 60 cracker samples (cream crackers and water and salt crackers) obtained from the metropolitan area of the state of Rio de Janeiro, RJ. Deoxynivalenol, zearalenone and fumonisin B1 were found, respectively, in 100, 50 and 28% of the analyzed samples. The maximum permissible limits established by Brazilian legislation for deoxynivalenol and zearalenone were not exceeded in the analyzed samples.

Two analytical methods were validated for determination of trichlorophenols, tetrachlorophenols and pentachlorophenol in drinking water. Limits of quantification were at least ten times lower than maximum permissible levels set by the Brazilian legislation, which are 200 ng mL-1 for 2,4,6-trichlorophenol and 9 ng mL-1 for pentachlorophenol. Chlorophenol levels were determined in tap water collected in the Municipality of Rio de Janeiro. 2,4,6-Trichlorophenol residues were detected in 36% of the samples, varying from 0.008 to 0.238 ng mL-1. All other analytes were below the limit of quantification. The validated methods showed to be suitable for application in routine quality control.