摘要:本课题研究的是：利用Ca2+与草酸根离子反应生成草酸钙沉淀，以火焰原子吸收法为检测手段，通过测定过量的Ca2+，从而间接求得食品中的草酸含量。此方法操作简便快捷。通过单因素和正交实验确定HCl用量、NaCl用量、乙醇用量、反应时间、反应温度对实验的影响。结果表明，在2.0mLCa2+标准溶液和1.0mL草酸标准溶液的反应体系中，HCl用量为1.0mL，NaCl用量为1.5mL，常温下反应15min为最佳实验条件，可用于实际样品的测定。用火焰原子吸收法，其检出限为0.0309mg/L，在最佳条件下对样品测定的相对标准偏差为0.59%~3.01%，加标回收率在97.3%~99.7%之间。其测定结果与国标测定结果相比较，相对误差在1.37%~9.83%之间，结果基本一致。

关键词 食品；间接原子吸收；草酸

Abstract:This paper researched that by using Ca2+ and oxalate ions to generate calcium oxalate precipitation with flame atomic absorption method for the determination of the overused Ca2+ to indirectly obtain the content of oxalate. Through single factor and orthogonal experiment to determine the dosage of HCl, NaCl and ethanol, reaction temperature and reaction time on experimental effects. The results showed that in the reaction system of 2.0mL Ca2+ standard solution and 1.0mL oxalate standard solution, adding 1.0mL HCl dosage and 1.5mL NaCl dosage and reacting for 15 minutes under the normal temperature were the best test condition, which could be used for analysis of real samples. By indirect atomic absorption method, the detection limit was 0.0309mg/L. The optimum conditions for determination of the relative standard deviation was between 0.59% and 3.01%. And the recovery rate was between 97.3% and 99.7%.  Comparing these determination results with those of national standard, the relative error was between 1.37% and 9.83%. The results were consistent.

Keywords  food  indirect atomic absorption spectrometry  oxalate