Speciation Analysis of Calcium in Milk by Flame Atomic Absorption Spectrophotometry

Abstract

Abstract: An effective method was developed for speciation analysis of calcium in milk by flame atomic absorption spectrophotometry. The effects of ethanol concentration, centrifuge temperature, centrifugal force and centrifugation time on protein sedimentation were discussed. The best conditions for separating calcium from samples were found to be protein sedimentation with 50% and centrifugation at 2 ℃ and 6000 × g for 6 min. The best La(NO3)3 concentration for releasing bound calcium was 6.00 mg/mL as determined by analyzing the effect on absorbance. Under the optimized conditions, the total calcium concentration of milk was determined to be 808.6 μg/mL and the bound and free calcium concentrations were 641.8 μg/mL and 173.0 μg/mL, which accounted for 79.4% and 21.4% of the total calcium, respectively. The precision (RSD) of the developed method was less than 3.3%, and the limit of detection was 0.11 μg/mL. The average spike recoveries of calcium was 97.0% with a RSD of 1.7%. This method was accurate, stable and applicable.

Key words: flame atomic absorption spectrophotometry (FAAS), speciation analysis, calcium

CLC Number:

O657.31

References

[1] 吴晓云, 向国强, 温圣平, 等. 微乳液进样-火焰原子吸收光谱测定食用油中的钙[J]. 河南工业大学学报: 自然科学版, 2010, 31(3): 8-11.
[2] 刘全德, 陈尚龙, 李勇, 等. 直接进样火焰原子吸收光谱法测定白酒中的钙[J]. 食品科学, 2011, 32(24): 224-227.
[3] 胡军, 常耀明, 高双斌, 等. 原子吸收光谱法测定血清中不同化学形态的铜、铁、锌[J]. 光谱学与光谱分析, 2008, 28(3): 700-703.
[4] GB/T 5009.92—2003 食品中钙的测定[S].
[5] 毕淑云, 孙艳涛, 刘何萍. 奶粉中钙、铁、锌的火焰原子吸收分光光度法研究[J]. 长春师范学院学报: 自然科学版, 2009, 28(3): 32-34.
[6] 张惠秦, 袁庆华. 火焰原子吸收光谱法测定苹果生长期中的钙含量[J]. 农业科学研究, 2008, 29(4): 45-47.
[7] ALEXANDRE J, ARIANE V Z, JANANA A, et al. Determination of calcium and magnesium in biodiesel by flame atomic absorption spectrometry using microemulsions as sample preparation[J]. Energy and Fuels, 2010, 24(3): 2109-2112.
[8] CUI Xiaoli, WANG Yingjun, SHE Xilin. Determination of Ca, K, Mg and Fe in four fish species by FAAS[J]. Journal of Ocean University of China (English Edition), 2010, 9(3): 235-238.
[9] 薛彦辉, 孙中国. 火焰原子吸收光谱法测定钙的样品预处理方法的应用进展[J]. 光谱实验室, 2011, 28(4): 1731-1734.
[10] 倪萌, 陈大伟, 刘莉, 等. 微波消解试样-火焰原子吸收光谱法测定蛋白粉中铜和钙[J]. 理化检验: 化学分册, 2010, 46(12): 1413-1417.
[11] LUO Yang, ZHANG Bo, CHEN Ming, et al. Rapid and Simultaneous Determination of Essential Minerals and Trace Elements in Human Milk by Improved Flame Atomic Absorption Spectroscopy (FAAS) with Microwave Digestion[J]. Analytical and Bioanalytical Chemistry, 2010,58(17): 9396-9400.
[12] 刘全德, 唐仕荣, 陈尚龙. 微波消解-释放剂辅助火焰原子吸收分光光度法测定蛋白质粉中的钙[J]. 食品科学, 2011, 32(16): 322-325.
[13] 刘圣昔, 李斌. 原子吸收光谱分析中化学干扰的消除方法[J]. 中国卫生检验杂志, 2007, 17(4): 744-745.
[14] 王北洪, 马智宏, 付伟利. 密封高压消解罐消解-原子吸收光谱法测定土壤重金属[J]. 工业工程学报, 2009, 24(增刊2): 255-259.
[15] 郭金英, 李丽, 刘开永, 等. 石墨炉原子吸收光谱直接进样法测定红葡萄酒中铅[J]. 食品科学, 2009, 27(18): 233-236.