采用《GB 5413.38—2016 食品安全国家标准 生乳冰点的测定》测定生乳的冰点时,对冰点仪校准液的制备实施质量控制,使用该方法配制的冰点校准液（标准溶液A和标准溶液B）精密度和稳定性符合标准要求。试验结果表明,采用高纯度（99.90%）氯化钠配制的校准液精密度小于±1.0 m℃;在（5±1）℃的冷藏条件下保存73 天,冰点校准液测定值与理论值的偏差均小于±2.0 m℃,满足实验室的校准分析需求。

When GB 5413.38-2016 national standard method is used to determine the freezing point of raw-milk,the quality control of the preparation of the freezing point calibration solution (standard solution A and standard solution B) is implemented,so that the precision and stability of the freezing point calibration solution meet the requirements of the standard.The experimental results showed that the precision of the calibration solution prepared with 99.90% high purity sodium chloride is less than ±1.0 m℃. Stored at (5±1) ℃ for 73 days,the deviation of freezing point values of freezing point calibration solution (standard solution A and standard solution B) from the theoretical value was less than ±2.0 m℃,meeting the needs of laboratory testing.