目的 通过比较不同水分测定方法, 研究适用于食品营养强化剂二水乳酸亚铁和三水乳酸亚铁的方法.方法 采用105 ℃直接干燥法、130 ℃直接干燥法、真空干燥法和卡尔·费休法测定二水乳酸亚铁和三水乳酸亚铁中水分含量.并比较干燥前后样品的色泽及三价铁含量.结果 105 ℃直接干燥法、130 ℃直接干燥法和真空干燥法仅适用于三水乳酸亚铁, 对二水乳酸亚铁不适用.卡尔·费休法可以检测出二水乳酸亚铁和三水乳酸亚铁中水分含量.结论 与105 ℃直接干燥法、130 ℃直接干燥法、真空干燥法相比, 卡尔·费休法更适合于二水乳酸亚铁和三水乳酸亚铁中水分含量的测定.建议《食品安全国家标准食品营养强化剂乳酸亚铁》中采用卡尔·费休法测定水分的含量.%Objective To investigate a suitable method for food nutrient supplement ferrous lactate dihydrate and trihydrate through the comparison of different methods for moisture content determination. Methods Direct drying method at 105 ℃, direct drying method at 130 ℃, vacuum drying method and Karl Fischer method were used for moisture content determination of ferrous lactate dihydrate and trihydrate. Color and ferric ion (Fe3+) content of the sample were compared before and after drying. Results Direct drying method at 105 ℃, direct drying method at 130 and vacuum drying method were suitable for ferrous lactate trihydrate and not suitable for ferrous lactate ℃dehydrate. The moisture content in ferrous lactate dihydrate and trihydrate could be detected by Karl Fischer method. Conclusion Compared with direct drying method at 105 ℃ , direct drying method at 130 ℃ and vacuum drying method, Karl Fischer method is more suitable for moisture content determination of ferrous lactate dihydrate and trihydrate.It is recommended that the moisture content should be determined by Karl Fisher method in National food safety standard for food nutrient supplement ferrous lactate.
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