奶粉中四环素检测能力验证研究

目的：设计并实施奶粉中四环素检测能力验证计划，评价实验室检测奶粉中四环素的技术能力和水平，促进各参加实验室对该类测试项目检测能力的提高。方法：参照CNAS-GL02，对参加该计划的21家食品药品检验实验室及第三方实验室的21份奶粉中的四环素测定结果进行稳健统计分析，用Z比分数评价实验室检测能力，并对离群数据从实验仪器、操作步骤、原始记录等方面进行技术分析。结果：在P<0.05显著水平，制备的300瓶样品均匀性符合要求且在整个计划周期内保持稳定，满足能力验证计划要求。21家参加验证的实验室中20家结果为满意结果，满意率为95.2%。结论：多数参加实验室检测能力评价为满意，表明奶粉中四环素检测水平总体良好。实验操作误差是造成个别实验室结果离群的主要原因。

Profciency Testing of the Determination of Tetracycline in Milk Powder

Objective: To design and conduct the profciency testing program for the determination of tetracycline in milk powder so as to assess the proficiency and level of the laboratories and to improve the proficiency of participant laboratories. Methods: Results of the determination of tetracycline in milk powder of the 21 food and drug testing laboratories and the third party laboratories obtained through the profciency testing program (PTP) were analyzed by robust statistics according to CNAS-GL02 and the profciency of the participant laboratories was evaluated by Z score. Moreover, the outlier data were analyzed from the following aspects, such as the experimental equipment, operating procedures, the original records, etc. Results: All 300 prepared samples were homogeneous and stable in the whole program period at signifcant level of P<0.05, which met the requirement of the PTP. 20 laboratories among the 21 laboratories participating in the profciency testing had satisfactory results, with a satisfaction rate of 95.2%. Conclusion: The majority of participant laboratories passed the proficiency testing with satisfactory results, indicating that the detection capability for the determination of tetracycline in milk powder was generally good. The main reason for the outlier results found in few laboratories was experimental operation error.