Determination and risk assessment of diazepam residues in aquatic products from China

A self-assembled solid-phase extraction column-ultra performance liquid chromatography-tandem mass spectrometer was established for the rapid and effective detection of diazepam in aquatic products from China. Carps, Grass carp, Hypophthalmichthys nobilis, Tilapia, Crucian Carp, Turbot, Shrimp, Hypophthalmichthys molitrix, Catfish and Mussel samples, a total of 50, were extracted using dipotassium hydrogen phosphate solution and acetonitrile, concentrated, and then eluted with acetonitrile-saturated n-hexane. Diazepam showed strong linearity with limits of detection and quantification from 0.03–0.08 μg/kg and 0.10–0.24 μg/kg, respectively. The matrix effect was low, at 5.5–10.9%, with average recoveries between 81.6–113% and relative standard deviations of 0.9–7.5%. Intraday and interday precision ranged from 2.0–5.6%, indicating good sensitivity, precision, and stability of the method for diazepam detection with minimal matrix effect. High-resolution mass spectrometry non-targeted screening was employed to distinguish unpurified from purified samples by visual analyses, such as principal component analysis (PCA), heat maps, and volcanic maps, identifying compounds containing hydroxyl, ester, quaternary ammonium, and phosphoric acid ester groups. The effect of the eluent on the separation mechanism of impurities from the target was also explored. Dietary risk assessment showed hazard quotient (HQ) values between 3.45 × 10−5 and 1.45 × 10−3, well below the threshold of 1, indicating that diazepam residues in aquatic products pose a low and acceptable risk to human health.