Determination of halquinol residual levels in animal-derived food products using liquid chromatography-tandem mass spectrometry.

A reliable and highly sensitive detection method based on liquid chromatography coupled with triple quadrupole electrospray tandem mass spectrometry (LC-MS/MS) analysis has been developed for determination and quantification of halquinol, including 5,7-dichloroquinolin-8-ol and 5-chloroquinolin-8-ol. The target analytes were extracted from porcine muscle, egg, milk, eel, flatfish and shrimp using a mixture of acetonitrile and ethyl acetate followed by liquid-liquid purification with n-hexane. The analytes were separated on an Agilent Eclipse XDB-C18 reversed-phase analytical column using 0.05% formic acid in distilled water and acetonitrile as mobile phases. Good linearity from six-point matrix-matched calibration was obtained with correlation coefficients (R2 ) ≥ 0.9904. Recoveries from three spiking levels (5, 10 and 20 μg/kg) ranged between 70.6 and 101.7% in various matrices with relative standard deviations ≤8.6%. Samples acquired from markets located in Seoul, Republic of Korea, tested negative for the target analytes. In conclusion, the proposed method is versatile and precise for the routine detection of halquinol residual levels in animal-derived food products intended for human consumption.