*2.9. Validation Test of ic-ELISA*

The ELISA validation was as follows: 20 aquatic products samples purchased from different areas were detected by ic-ELISA. The LOD and LOQ were calculated from the sum of the 20 blank samples. The precision and accuracy were evaluated by analyzing the recovery and intra- and inter-assay variations (CV) via the repeated analysis of the spiked samples. Briefly, three different concentrations of PYR (2, 4, and 8 μg/L) were spiked into the blank samples, and three intra-batch tests and five inter-batch tests were employed for ELISA. The recovery and CV were calculated as follows: recovery (%) = (conc. measured/conc. spiked) × 100; CV (%) = sample standard deviation/sample average × 100%.
