Low temperature clean-up combined with magnetic solid phase extraction for rapid and sensitive detection of crystal violet and malachite green in eels

Crystal violet (CV) and malachite green (MG) are antibiotics used in aquaculture, regulated due to their teratogenicity and potential carcinogenic risk. Detecting them in seafood is challenging due to low concentrations and complex matrices, especially fat interference. In this study, low-temperature clean-up removed fat interference, and magnetic nanoparticles preconcentrated the target analytes, achieving high sensitivity, low cost, and easy operation. The proposed method achieved detection limits of 0.18 ng g −1 and 0.54 ng g −1 for CV and MG, respectively, with quantification limits of 0.21 ng g −1 and 0.60 ng g −1 . The intra- and inter-day relative standard deviations were 1.45 %–4.81 % and 4.53 %–7.60 %, respectively, indicating good reproducibility. Recovery rates were 83.19 %–112.88 %, with stable adsorption capacity after 25 cycles. This method offers an ideal solution for rapid screening of CV and MG in seafood for batch samples in markets, stock houses, and on-site situations, adaptable to various analytes and matrices.