摘要
[目的]确定分光光度法测定酸奶中钙含量的最佳操作条件。[方法]利用钙指示剂与钙的显色反应,研究影响其稳定性的因素,确定分光光度法测定酸奶中钙含量的最佳操作条件。[结果]最佳操作条件为：在536nm的测定波长下,加入pH值为5.33的乙酸-乙酸钠缓冲溶液5ml,0.05%钙指示剂的用量为2ml,显色时间10min,在此条件下,钙含量在0～1.6μg/ml的浓度范围内遵守比尔定律,体系表观摩尔吸光系数ε536nm为3.75102L/（mol·cm）,且17种常见共存离子均不产生干扰。分光光度法测定酸奶中钙含量的相对标准偏差小于2.50%,加标回收率为96%～100%。[结论]分光光度法测定酸奶中的钙含量显示出较高的灵敏度,具有稳定性好、准确度高、试剂和仪器廉价、操作简便快速等优点。
[ Objective] The aim was to determine the best operating conditions in measuring the content of calcium in yoghurt by spectrophotometry. [Method] The calcium indicator and color reaction of calcium was utilized to study the factors that affected its stability, the optimum operating conditions in measuring the calcium content in yoghurt by spectrophotometry were determined. [Result] The optimum operating conditions was： under the detection wavelength of 536 nm, adding 5 ml of acetic acid-sodium acetate buffer solution with pH 5.33and 2 ml of 0,05% calcium indicator and coloration time of 10 min., under which, the calcium content abide by the Beer Law within the concentration range of 0 - 1.6μg/ml, the apparent molar absorption coefficient ε536nm of the system was 3.751 02 L/（mol·cm）,and all the 17 kinds of common coexisting ions did not produce disturbance. The relative standard deviation in measuring the calcium content in yoghurt by spectrophotometry was lass than 2.50% ,and the recovery of standard addition was 96% - 100%. [ Conclusion ] The determination of the calcium content in yoghurt by spectrophotometry showed a high sensitivity and had advantages of good stability, high accuracy, cheap reagent and instntments as well as simple and rapid operation.
出处
《安徽农业科学》
CAS
北大核心
2008年第22期9352-9353,共2页
Journal of Anhui Agricultural Sciences
关键词
分光光度法
酸奶
钙
Spectrophotometry
Yoghurt
Calcium
