Tetrodotoxin (TTX) was simultaneously detected in the fresh and heat-processed aquatic products by high-performance liquid chromatography–tandem mass spectrometry method. The detection conditions were investigated, including the chromatography column and mobile phase. Based on the optimized parameters, a sensitive determination method of TTX was established. The proposed method featured the merits of a good linear relationship between signal and TTX concentration (R2 = 0.9998), a wide detection matrix-based range of 0.2–100 ng/g, and a low detection limit of 0.2 ng/g, etc. The spiked assays evidenced its accuracy and reliability with recoveries of 90.5–107.2%. Finally, the developed method was simultaneously successfully applied in the determination of TTX in various fresh and heat-processed aquatic products.

Antibiotic drug residues are crucial to ensure food safety and minimize risk to human health. Herein, a sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed and validated for the determination of antibiotic residues (mainly amphenicols) consisting of chloramphenicol (CAP), thiamphenicol (TAP), florfenicol (FF), and florfenicol amine (FFA) in aquatic products. Amphenicols were well separated on a Kinetex F5 (100 mm × 3.0 mm, 2.6 µm) chromatographic column with the mobile phases of 1 mM ammonium acetate aqueous solution and methanol solution and measured after positive and negative electrospray ionizations using four internal standards. To our knowledge, it was the first time to report the good performance of F5 column and four internal standards for the determination of amphenicols. The established method featured a good linear relationship between chromatographic peak area ratios and the concentrations of amphenicols (R2 > 0.992), a wide and low detection matrix-based range of 0.01-5 μg/L, a low detection limit of 0.01 μg/kg, etc. The spiked assays evidenced the accuracy and reliability of the developed method with the recoveries between 84.0 and 105 %, the intraday relative standard deviations (RSDs) over the range of 0.769-13.7 %, and the interday RSDs over the range of 0.582-13.3 %. Finally, the proposed method was applied to investigate amphenicol residues in various aquatic products, including fish, shrimp, crab, shellfish, and other aquatic species.

The pharmacokinetics and tissue residues of vancomycin in crucian carp (Carassius auratus) were studied after oral administration of a single dosage of 1 mg/kg body weight at water temperature of 18°C. The drug concentration-time data were fitted using a two-compartment open model with first-order absorption. The vancomycin concentrations in plasma and tissues including muscle, liver and kidney were analyzed by means of liquid chromatography-tandem mass spectrometry. As a result, the plasma absorption rate constant of vancomycin was 3.75/hr and the time point of maximum concentration in plasma was 3.0 hr respectively. The maximum concentration of vancomycin in plasma was 216.58 μg/L. The distribution half-life and the elimination half-life in plasma were 6.69 hr and 190 hr, as well as the absorption half-life of plasma was 0.19/hr. The area under the plasma concentration-time curve of plasma was 15.12 mg hr/L. The apparent volume of distribution of plasma was estimated to be 4.45 L/kg and the total body clearance was computed as 0.061 L hr −1 kg −1 . In addition, the maximum tissue concentrations of vancomycin were in the order of liver > kidney > muscle. To guarantee the safety of tissue samples for consumption, it was suggested that the withdrawal time should not be less than 30 days at 18°C. All these results may provide guidance for future vancomycin treatment in aquaculture. K E Y W O R D S crucian carp, pharmacokinetic, residue, vancomycin