Abstract: Quality control samples were independently developed by adding different concentrations of florfenicol to blank eggs. According to CNAS-GL003:2018 Guidelines on Evaluating the Homogeneity and Stability of Samples used for proficiency Testing, their homogeneity and stability were evaluated by using liquid chromatography-mass spectrometry (LC-MS) specified in GB/T 22338-2008 as a reference method. At the same time, the factors affecting the stability of the quality control samples were studied, and reference values for the quality control samples were determined jointly by six laboratories. The results showed that both the non-freeze-dried (liquid) and freeze-dried (solid) quality control samples had good homogeneity and stability. Sample state and storage temperature had an impact on the stability of the quality control samples. The freeze-dried quality control samples were stable at ?18 ℃ for 12 months. The certified values for the freeze-dried quality control samples at three concentration levels were 0.23, 0.39 and 1.92 μg/kg, and these quality control samples could be applied for process quality control in the fields of rapid testing and conventional laboratory detection.

Key words: florfenicol; quality control samples; homogeneity; stability; characterization