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目的建立石墨化碳黑净化-二苯碳酰二肼衍生-分光光度法测定着色明胶空心胶囊中六价铬的含量。方法样品经磷酸盐缓冲液Ⅰ提取,80℃水浴振荡1 h,碱性条件下用石墨化碳黑脱除色素,二苯碳酰二肼丙酮溶液酸性条件下衍生显色,10 mm石英比色皿比色,采用分光光度法在540 nm波长下检测,扣除本底后以外标法定量。结果 50 mg石墨化碳黑粉末(graphitized carbon black,GCB)对于明胶空心胶囊的着色剂具有较好的脱除效果,GCB在待净化液pH大于12.5的条件下对Cr(Ⅵ)的吸附作用不明显,回收率可达90%以上。样品中Cr(Ⅲ)的存在对于本方法测定Cr(Ⅵ)无显著影响。根据使用的比色皿光程,方法检出限为1.6 mg/kg或更低。结论本方法快速准确,适用于明胶空心胶囊中六价铬的检测。
Objective To establish a graphitized carbon black purification - diphenylcarbazide derivative - spectrophotometric determination of hexavalent chromium in colored gelatin hollow capsules. Methods The samples were extracted with phosphate buffer Ⅰ and shaken in a water bath at 80 ℃ for 1 h. The pigment was removed with graphitized carbon black under alkaline conditions. The diphenylcarbazide acetone solution was derivatized under acidic conditions. The 10 mm quartz colorimetric Dish colorimetric, spectrophotometric detection at 540 nm wavelength, after subtracting the amount of external standard method. Results Graphitized carbon black (GCB) showed a good removal effect on the gelatin hollow capsules. The adsorption of Cr (Ⅵ) by GCB was not more than 12.5 Obviously, the recovery rate of up to 90%. The presence of Cr (Ⅲ) in the sample has no significant effect on the determination of Cr (Ⅵ) by this method. The method detection limit is 1.6 mg / kg or lower, depending on the cuvette path used. Conclusion The method is rapid and accurate and suitable for the determination of hexavalent chromium in gelatin hollow capsules.