毛细管区带电泳-间接紫外法快速测定食品中的甜蜜素

Rapid determination of cyclamate in foods bycapillaryzone electrophoresis with indirect ultraviolet detection

建立了毛细管区带电泳-间接紫外法快速测定食品中甜蜜素的新方法。液体样品用超纯水稀释后直接进样;固体样品经粉碎或剪碎后用超纯水超声提取后离心,上清液直接进样或用水稀释后进样。以未涂敷石英毛细管(80 cm×75μm,有效长度:70 cm)为分离柱,以2 mmol/L苯甲酸钠+10 mmol/L碳酸钠+0.5 mmol/L十六烷基三甲基溴化铵为分离缓冲液;于200 nm波长处检测。检出限为8.9 mg/kg(S/N=3),定量限为26.7 mg/kg(S/N=9)。低、中、高添加水平的加标回收率分别为93.4%、100.3%及101.9%,相应的RSD分别为6.7%、2.0%及2.2%(n=5)。日内及日间精密度分别为2.6%和4.5%。整个分析过程无需有机溶剂。在能力验证样品的分析结果与国家标准方法的结果相吻合的基础上,分析了7件食品样品,获满意结果。

A new method for the rapid determination of cyclamate in foods by capillary zone electrophoresis（ CZE）with indirect ultraviolet detection was developed. The separation was carried out with an uncoated fused-silica capillary（75 μm i. d.,total length 80 cm,effective length 70 cm）. The separation buffer consisted of 2 mmol / L sodium benzoate,10 mmol / L sodi-um carbonate and 0. 5 mmol / L hexadecyl trimethyl ammonium bromide. The separation voltage was -30 kV and the detection wavelength was 200 nm. The liquid samples could be directly injected after dilution with ultrapure water. The solid samples were first grounded or cut into pieces,and then extracted with ultrapure water. Then,the mixed solution was centrifuged. The supernatant was directly injected or injected after dilution with ultrapure water. The analytes were determined by external calibration. The limits of detection（ S / N = 3）and the limits of quantification（ S / N = 9 ） were 8. 9 mg / kg and 26. 7 mg / kg,respectively. The linear range between the corrected peak area and the mass concentration was from 1. 2 mg / L to 80 mg / L with the correlation coefficient of 0. 999 9. The average spiked recoveries of five replicates at three spiked levels（2. 5,10 and 20 mg / L）were 93. 4% ,100. 3% and 101. 9% with the relative standard deviations of 6. 7% ,2. 0% and 2. 2% ,respectively. The intra- and inter-day precisions of the method were 2. 6% and 4. 5% ,respectively. The method is simple and rapid with minimal sample pretreatment and reagent consumption. No solvent was needed throughout the whole＆amp;nbsp;process of analysis. The analysis could be completed within 11 min（6 min for rinsing and 5 min for separation）. The newly established method was used for the determination of cyclamate in a proficiency test sample. The results were in good agreement with that of the National Standard method,which illustrated the accuracy of the present method. Then,seven food samples were analyzed using the current new method and satisfactory results were obtained.