Investigation of the fate of trifluralin in shrimp

Juvenile Pacific white shrimp (Litopenaeus vannamei) were exposed to trifluralin at 0.1 and 0.01 mg L(-1) for 72 h under controlled conditions. Samples of shrimp and tank water were collected at intervals up to 48 days after exposure. Analysis of the shrimp tissues by gas chromatography-mass spectrometry (GC-MS) and ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-qToF-MS) in combination with profiling and metabolite identification software (Agilent MET-ID and Mass Profiler Professional) detected the presence of parent trifluralin together with two main transformation products (TPs), 2-ethyl-7-nitro-5-(trifluoromethyl)benzimidazole (TP1) and 2-amino-6-nitro-4-(trifluoromethyl)phenyl)propylamine (TP2). The highest concentration of trifluralin, determined by GC-MS, was 120 μg kg(-1) at 0 day withdrawal. Residues of trifluralin (CCα = 0.25 μg kg(-1), CCβ = 0.42 μg kg(-1)) were detectable for up to 7 days after exposure. Similarly, the highest concentrations of TP1 and TP 2, determined by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS), were 14 and 18 μg kg(-1), respectively. Residues of TP1 (CCα = 0.05 μg kg(-1), CCβ = 0.09 μg kg(-1)) and TP2 (CCα = 0.1 μg kg(-1), CCβ = 0.17 μg kg(-1)) were detectable for up to 4 and 24 withdrawal days, respectively.