自动顶空气相色谱法测定饮料中的甜蜜素

Determination of sodium cyclamate in drinks by automatic headspace gas chromatography

目的建立采用自动顶空进样器测定饮料中甜蜜素的气相色谱测定方法。方法在硫酸酸性条件下甜蜜素与亚硝酸钠反应生成易气化的环己醇亚硝酸酯,在恒温的密闭环境中,环己醇亚硝酸酯在气、液两相间分配达到动态平衡。此时环己醇亚硝酸酯在气相中的浓度与甜蜜素含量成正比。顶空法提取并进样,使用HP-5毛细管色谱柱采用程序升温方式进行分离,用带有氢火焰离子化检测器(FID)的气相色谱仪进行检测,以保留时间定性,外标法定量。结果甜蜜素的线性范围为0.02 mg/ml^1.0 mg/ml,线性关系良好,相关系数(r)为0.999 8,检出限为0.4 mg/kg,回收率为90.5%~102.0%,相对标准偏差(RSD)为1.82%。结论该方法具有干扰少、简便高效、灵敏准确等优点,适合各种饮料中甜蜜素的测定,具有较广阔的应用前景和推广价值。

Objective To establish a method for the determination of sodium cyclamate in drinks with automatic headspace gas chromatography. Methods Sodium cyclamate and sodium nitrite reacted to cyclohexanol nitrite which was gasified easily under the condition of sulfuric acid. In the constant temperature and airtight environment,cyclohexanol nitrite distributed to achieve a dynamic equilibrium in the phases of gas and liquid. The concentration of cyclohexanol nitrite in gas phase was in the positive proportion to the content of sodium cyclamate. The cyclohexanol nitrite was extracted and injected by headspace technology.Meanwhile,the sodium cyclamate was separated with HP- 5 capillary column and detected through the FID of GC detector by controlling the temperature,and quantified by retention time and external standard method. Results The linear rang of the sodium cyclamate was among 0. 02 mg / ml- 1. 0 mg / ml with good linear relationship,and the correlation coefficient（ r） was0. 999 8. The determination limit was 0. 4 mg / kg,and the recoveries ranged among 90. 5%- 102. 0%. The RSD was 1. 82%.Conclusion The method was simple,efficient,selective,accurate with less interference. It was suitable for the determination of the sodium cyclamate in different drinks. In a word,it has a wide application and prospects.