应用CO_(2)处理分析再造烟叶中的碳酸钙

Determination of calcium carbonate in reconstituted tobacco by CO_(2) treatment

为消除磷酸钙对再造烟叶中碳酸钙测定的干扰,准确测定碳酸钙的质量百分数,用CO_(2)与碳酸钙反应生成可溶的碳酸氢钙,再采用离子色谱法测定CO_(2)反应前后Ca^(2+)质量浓度的变化,进而分析碳酸钙的质量百分数。验证了方法的可行性,考察了方法的重复性、回收率、检测限和定量限,并测定了不同再造烟叶样品中碳酸钙的质量百分数。结果表明:(1)比较3种不同的前处理方法,应用CO_(2)处理可以实现碳酸钙与磷酸钙的分离,准确测定再造烟叶中碳酸钙的质量百分数。(2)该方法的重复性较好、回收率较高,重复测定5次的相对标准偏差(RSD)为2.69%,回收率介于95%~102%之间;方法的检测限为0.12%,定量限为0.39%。(3)不同再造烟叶样品中碳酸钙的质量百分数差异较大,所测5种样品中碳酸钙的质量百分数介于2%~4%之间。综上,该方法方便、快捷,适用于再造烟叶以及复杂钙盐体系中碳酸钙质量百分数的准确测定。

To eliminate the interference of calcium phosphate on the determination of calcium carbonate in reconstituted tobacco and to develop an accurate method for determining the mass percentage of calcium carbonate,CO_(2) was applied to react with calcium carbonate in reconstituted tobacco samples to form water-soluble calcium bicarbonate.Following the treatment,the variation of calcium ion concentration after CO_(2) treatment was determined by ion chromatography to analyze the mass percentage of calcium carbonate.The feasibility of the method was verified based on the repeatability,recovery,limit of detection(LOD),and limit of quantification(LOQ).The results showed that:1)Calcium carbonate could be separated from calcium phosphate by CO_(2) treatment,and the mass percentage of calcium carbonate in the reconstituted tobacco samples could be accurately determined using three different pretreatment methods.2)This method showed better repeatability and recovery with a relative standard deviation(RSD,n=5)of 2.69%and recoveries in the range of 95%-102%.The LOD and LOQ were 0.12%and 0.39%,respectively.3)The variation of the mass percentage of calcium carbonate in different reconstituted tobacco samples was large and varied from 2%to 4%in five reconstituted tobacco samples.In conclusion,this method was convenient,rapid,and suitable for accurate determination of the mass percentage of calcium carbonate in reconstituted tobacco and other complex calcium salt reconstituted tobacco systems.