微波消解-浊点萃取-火焰原子吸收光谱法测定空心胶囊中铬含量

Microwave Digestion-Cloud Point Extraction of Chromium in Hollow Capsules Prior to Flame Atomic Absorption Spectrometry

研究了微波消解-浊点萃取-火焰原子吸收光谱法(FAAS)测定空心胶囊中痕量铬的方法。空心胶囊通过微波消解,以二乙基二硫代氨基甲酸钠(DDTC)为络合剂络合消解液中铬(Ⅵ),非离子表面活性剂Triton X-114为萃取剂,结合FAAS测定空心胶囊中痕量铬,与《中国药典》(2010版)检测方法具有较好一致性。考察了溶液的pH值、络合剂和表面活性剂浓度、平衡温度和时间等条件对浊点萃取效果的影响。在最优条件下,铬(Ⅵ)线性范围为0～10μg/mL,检出限(3σ)为7.6ng/mL,相对标准偏差为1.5%(n=10),回收率在95%～102%之间。方法灵敏度高,重复性好,适合于胶囊中铬的日常检测。

The detection of trace chromium in the hollow capsule was performed by microwave digestion-cloud point extraction（CPE） combined with flame atomic absorption spectrometry（FAAS）. The method was based on the formation of hydrophobic complexes between digested chromium（VI） and diethyldithiocarbamic acid sodium salt（DDTC）, and DDTC-Cr was extracted into non-ion surfactant Triton X-114 for FAAS determination. The method has good consistence with that of Chinese Pharmacopeia（2010）. The effects of experimental conditions such as pH, concentrations of chelating agent and surfactant, equilibration temperature and time on CPE were investigated. Under the optimum conditions,the linear range is 0-10 μg/mL with detection limit（3σ） of 7.6 ng/mL and relative standard deviation of 0.6%-1.8% （n= 10）, and the recoveries are between 95 %and 102%. The method is highly sensitive, repeatable, and suitable for daily detection of chromium in the capsule.