Rapid screening and confirmation of 36 sulfonamide and four tetracycline drugs in aquatic products by ultra performance liquid chromatography-time-of-flight-mass spectrometry with pass-through solid-phase extraction

In order to achieve rapid and accurate analysis of sulfonamide and tetracycline drugs in aquatic products， a universal method for the rapid screening and confirmation of multiple residues of 36 sulfonamide and four tetracycline drugs was established. The method combined the PRiME HLB solid-phase extraction（SPE） column with ultra performance liquid chromatography-time-of-flight-mass spectrometry（UPLC-TOF-MS）. Samples were extracted using 80% acetonitrile aqueous solution（containing 0.05 mol/L Na₂EDTA）. The resultant solution was purified by PRiME HLB SPE column and then blown to nearly dry with nitrogen. It was redissolved with 5% methanol aqueous solution and finally passed through a polytetrafluoroethylene filter membrane. Gradient elution was carried out using 0.1% formic acid aqueous solution（containing 2 mmol/L ammonium acetate solution） and 0.1% formic acid methanol solution as the mobile phases， and scanning was performed using the information dependent acquisition（IDA） mode of TOF-MS. The rapid screening and confirmation of the target compounds were achieved through information such as the precise <italic>m/z</italic> of the parent ion， retention time， isotope abundance ratio， and comparison with the secondary daughter-ion spectral library， and quantification is carried out by the external standard method（using the matrix-matched mixed standard solution）. The UPLC elution program was optimized to achieve good separation of 17 isomers in seven groups within 13 min. By optimizing the collision energy of the secondary mass spectrometry， a comprehensive secondary fragment ion mass spectrum is obtained. Combined with the collected information such as the chemical molecular formula and CAS number of the compounds， a complete database is established. In addition， the procedures of two purification columns（PRiME HLB column and HLB column） was compared， and the composition of the extraction solvent and the type of filter membrane were optimized to obtain the optimal experimental conditions. The methodological validation results indicated that 36 sulfonamide and four tetracycline drugs had a good linear relationship within the range of 2‒50 μg/L， and the correlation coefficients were all ≥0.990 68. Except for sulfanilamide and ambamide， whose LOQs were 10 μg/kg， the LOQs of the other 38 drugs were all 5 μg/kg. Using grass carp meat， shrimp meat， scallop meat and mackerel meat as blank matrix samples， at three spiked levels（5， 10 and 20 μg/kg）， the recoveries of the 40 drugs were 62.8%‒116.4%， and the RSDs were ≤13.8%. This method is simple to operate， has good stability and high universality， and can meet the requirements of rapid screening and confirmation of sulfonamide and tetracycline drugs in aquatic products.