Residual determination of anesthetic menthol in fishes by SDME/GC-MS.

The SDME-GC/MS method was applied to residual determination of anesthetic menthol in fish. The extractions took place from the headspace of the sample using 1.8µL of octane as the extraction solvent. To obtain the ideal extraction condition, was used Response Surface Methodology, defining: extraction time 15min, temperature 30°C and salt 3g. The method showed LOD and LOQ of 0.021 and 1.56µgL respectively, recovery of 94% and R of 0.9997. The analyzes were performed on tilapia fillets anesthetized in five concentrations between 5 and 15×10µgL and with times of slaughter after anesthesia of 0, 12, 24 and 48h. It was determined that 48h is the required residual period for total metabolization of menthol in the fishes' organisms. This methodology becomes promising regarding the establishment of protocols to regulatory the use of menthol as an anesthetic in aquaculture.