Evaluation of pyraoxystrobin bioconcentration in zebrafish ( Danio rerio ) using modified QuEChERS extraction.

Pyraoxystrobin is a novel strobilurin fungicide that is widely used on many crops. The high log K-ow of pyraoxystrobin implies that it tends to accumulate in aquatic organisms. This study optimized the sorbents of QuEChERS (quick, easy, cheap, effective, rugged, and safe) using C-13-labelled pyraoxystrobin as the internal standard (IS). It has been established a QuEChERS-LC-MS/MS IS method to study the bioconcentration and elimination of pyraoxystrobin in zebrafish (Danio rerio). The results indicated that the method had satisfactory linearity between 0.234 and 15 mu g L-1 (R-2 = 0.9996). The limits of detection (LOD) and quantification (LOQ) for pyraoxystrobin were 0.01 and 0.03 mu g L-1, respectively. The LOQs of the method for water and zebrafish were 0.05 mu g L-1 and 0.01 mg/kg, respectively. The mean recovery of pyraoxystrobin in zebrafish and water at fortification levels of 0.01-0.3 mg kg(-1) and 0.05-1.5 mu g L-1 ranged from 98.31 to 105.61% and 101.87 to 108.48%, respectively, with a % RSD (relative standard deviation) of 0.94-3.57%. The bioconcentration has been evaluated. The bioconcentration factors for pyraoxystrobin in zebrafish were 1,792 and 3,505 after exposure to 0.5 mu g L-1 for 168 h and 0.05 mu g L-1 for 216 h, respectively. The half-life of pyraoxystrobin in zebrafish was 9.0-9.5 d.